We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
example code bug in remote_server_context.py
In file: 
https://github.com/riptideio/pymodbus/blob/master/examples/contrib/remote_server_context.py#L160

`RemoteServerContext` not have `self.__slaves`

more in:
https://github.com/riptideio/pymodbus/commit/fec7ac37f37e3d29196f6775c24a833bf9881539

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `examples/contrib/remote_server_context.py`
Content:
```
1 '''
2 Although there is a remote server context already in the main library,
3 it works under the assumption that users would have a server context
4 of the following form::
5 
6     server_context = {
7         0x00: client('host1.something.com'),
8         0x01: client('host2.something.com'),
9         0x02: client('host3.something.com')
10     }
11 
12 This example is how to create a server context where the client is
13 pointing to the same host, but the requested slave id is used as the
14 slave for the client::
15 
16     server_context = {
17         0x00: client('host1.something.com', 0x00),
18         0x01: client('host1.something.com', 0x01),
19         0x02: client('host1.something.com', 0x02)
20     }
21 '''
22 from pymodbus.exceptions import NotImplementedException
23 from pymodbus.interfaces import IModbusSlaveContext
24 
25 #---------------------------------------------------------------------------#
26 # Logging
27 #---------------------------------------------------------------------------#
28 
29 import logging
30 _logger = logging.getLogger(__name__)
31 
32 #---------------------------------------------------------------------------#
33 # Slave Context
34 #---------------------------------------------------------------------------#
35 # Basically we create a new slave context for the given slave identifier so
36 # that this slave context will only make requests to that slave with the
37 # client that the server is maintaining.
38 #---------------------------------------------------------------------------#
39 
40 class RemoteSingleSlaveContext(IModbusSlaveContext):
41     ''' This is a remote server context that allows one
42     to create a server context backed by a single client that
43     may be attached to many slave units. This can be used to
44     effectively create a modbus forwarding server.
45     '''
46 
47     def __init__(self, context, unit_id):
48         ''' Initializes the datastores
49 
50         :param context: The underlying context to operate with
51         :param unit_id: The slave that this context will contact
52         '''
53         self.context = context
54         self.unit_id = unit_id
55 
56     def reset(self):
57         ''' Resets all the datastores to their default values '''
58         raise NotImplementedException()
59 
60     def validate(self, fx, address, count=1):
61         ''' Validates the request to make sure it is in range
62 
63         :param fx: The function we are working with
64         :param address: The starting address
65         :param count: The number of values to test
66         :returns: True if the request in within range, False otherwise
67         '''
68         _logger.debug("validate[%d] %d:%d" % (fx, address, count))
69         result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)
70         return result.function_code < 0x80
71 
72     def getValues(self, fx, address, count=1):
73         ''' Validates the request to make sure it is in range
74 
75         :param fx: The function we are working with
76         :param address: The starting address
77         :param count: The number of values to retrieve
78         :returns: The requested values from a:a+c
79         '''
80         _logger.debug("get values[%d] %d:%d" % (fx, address, count))
81         result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)
82         return self.__extract_result(self.decode(fx), result)
83 
84     def setValues(self, fx, address, values):
85         ''' Sets the datastore with the supplied values
86 
87         :param fx: The function we are working with
88         :param address: The starting address
89         :param values: The new values to be set
90         '''
91         _logger.debug("set values[%d] %d:%d" % (fx, address, len(values)))
92         self.context.set_callbacks[self.decode(fx)](address, values, self.unit_id)
93 
94     def __str__(self):
95         ''' Returns a string representation of the context
96 
97         :returns: A string representation of the context
98         '''
99         return "Remote Single Slave Context(%s)" % self.unit_id
100 
101     def __extract_result(self, fx, result):
102         ''' A helper method to extract the values out of
103         a response. The future api should make the result
104         consistent so we can just call `result.getValues()`.
105 
106         :param fx: The function to call
107         :param result: The resulting data
108         '''
109         if result.function_code < 0x80:
110             if fx in ['d', 'c']: return result.bits
111             if fx in ['h', 'i']: return result.registers
112         else: return result
113 
114 #---------------------------------------------------------------------------#
115 # Server Context
116 #---------------------------------------------------------------------------#
117 # Think of this as simply a dictionary of { unit_id: client(req, unit_id) }
118 #---------------------------------------------------------------------------#
119 
120 class RemoteServerContext(object):
121     ''' This is a remote server context that allows one
122     to create a server context backed by a single client that
123     may be attached to many slave units. This can be used to
124     effectively create a modbus forwarding server.
125     '''
126 
127     def __init__(self, client):
128         ''' Initializes the datastores
129 
130         :param client: The client to retrieve values with
131         '''
132         self.get_callbacks = {
133             'd': lambda a, c, s: client.read_discrete_inputs(a, c, s),
134             'c': lambda a, c, s: client.read_coils(a, c, s),
135             'h': lambda a, c, s: client.read_holding_registers(a, c, s),
136             'i': lambda a, c, s: client.read_input_registers(a, c, s),
137         }
138         self.set_callbacks = {
139             'd': lambda a, v, s: client.write_coils(a, v, s),
140             'c': lambda a, v, s: client.write_coils(a, v, s),
141             'h': lambda a, v, s: client.write_registers(a, v, s),
142             'i': lambda a, v, s: client.write_registers(a, v, s),
143         }
144         self.slaves = {} # simply a cache
145 
146     def __str__(self):
147         ''' Returns a string representation of the context
148 
149         :returns: A string representation of the context
150         '''
151         return "Remote Server Context(%s)" % self._client
152 
153     def __iter__(self):
154         ''' Iterater over the current collection of slave
155         contexts.
156 
157         :returns: An iterator over the slave contexts
158         '''
159         # note, this may not include all slaves
160         return self.__slaves.iteritems()
161 
162     def __contains__(self, slave):
163         ''' Check if the given slave is in this list
164 
165         :param slave: slave The slave to check for existance
166         :returns: True if the slave exists, False otherwise
167         '''
168         # we don't want to check the cache here as the
169         # slave may not exist yet or may not exist any
170         # more. The best thing to do is try and fail.
171         return True
172 
173     def __setitem__(self, slave, context):
174         ''' Used to set a new slave context
175 
176         :param slave: The slave context to set
177         :param context: The new context to set for this slave
178         '''
179         raise NotImplementedException() # doesn't make sense here
180 
181     def __delitem__(self, slave):
182         ''' Wrapper used to access the slave context
183 
184         :param slave: The slave context to remove
185         '''
186         raise NotImplementedException() # doesn't make sense here
187 
188     def __getitem__(self, slave):
189         ''' Used to get access to a slave context
190 
191         :param slave: The slave context to get
192         :returns: The requested slave context
193         '''
194         if slave not in self.slaves:
195             self.slaves[slave] = RemoteSingleSlaveContext(self, slave)
196         return self.slaves[slave]
197
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/examples/contrib/remote_server_context.py b/examples/contrib/remote_server_context.py
--- a/examples/contrib/remote_server_context.py
+++ b/examples/contrib/remote_server_context.py
@@ -141,6 +141,7 @@
             'h': lambda a, v, s: client.write_registers(a, v, s),
             'i': lambda a, v, s: client.write_registers(a, v, s),
         }
+        self._client = client
         self.slaves = {} # simply a cache
 
     def __str__(self):
@@ -157,7 +158,7 @@
         :returns: An iterator over the slave contexts
         '''
         # note, this may not include all slaves
-        return self.__slaves.iteritems()
+        return iter(self.slaves.items())
 
     def __contains__(self, slave):
         ''' Check if the given slave is in this list

{"golden_diff": "diff --git a/examples/contrib/remote_server_context.py b/examples/contrib/remote_server_context.py\n--- a/examples/contrib/remote_server_context.py\n+++ b/examples/contrib/remote_server_context.py\n@@ -141,6 +141,7 @@\n             'h': lambda a, v, s: client.write_registers(a, v, s),\n             'i': lambda a, v, s: client.write_registers(a, v, s),\n         }\n+        self._client = client\n         self.slaves = {} # simply a cache\n \n     def __str__(self):\n@@ -157,7 +158,7 @@\n         :returns: An iterator over the slave contexts\n         '''\n         # note, this may not include all slaves\n-        return self.__slaves.iteritems()\n+        return iter(self.slaves.items())\n \n     def __contains__(self, slave):\n         ''' Check if the given slave is in this list\n", "issue": "example code bug in remote_server_context.py\nIn file: \r\nhttps://github.com/riptideio/pymodbus/blob/master/examples/contrib/remote_server_context.py#L160\r\n\r\n`RemoteServerContext` not have `self.__slaves`\r\n\r\nmore in:\r\nhttps://github.com/riptideio/pymodbus/commit/fec7ac37f37e3d29196f6775c24a833bf9881539\n", "before_files": [{"content": "'''\nAlthough there is a remote server context already in the main library,\nit works under the assumption that users would have a server context\nof the following form::\n\n    server_context = {\n        0x00: client('host1.something.com'),\n        0x01: client('host2.something.com'),\n        0x02: client('host3.something.com')\n    }\n\nThis example is how to create a server context where the client is\npointing to the same host, but the requested slave id is used as the\nslave for the client::\n\n    server_context = {\n        0x00: client('host1.something.com', 0x00),\n        0x01: client('host1.something.com', 0x01),\n        0x02: client('host1.something.com', 0x02)\n    }\n'''\nfrom pymodbus.exceptions import NotImplementedException\nfrom pymodbus.interfaces import IModbusSlaveContext\n\n#---------------------------------------------------------------------------#\n# Logging\n#---------------------------------------------------------------------------#\n\nimport logging\n_logger = logging.getLogger(__name__)\n\n#---------------------------------------------------------------------------#\n# Slave Context\n#---------------------------------------------------------------------------#\n# Basically we create a new slave context for the given slave identifier so\n# that this slave context will only make requests to that slave with the\n# client that the server is maintaining.\n#---------------------------------------------------------------------------#\n\nclass RemoteSingleSlaveContext(IModbusSlaveContext):\n    ''' This is a remote server context that allows one\n    to create a server context backed by a single client that\n    may be attached to many slave units. This can be used to\n    effectively create a modbus forwarding server.\n    '''\n\n    def __init__(self, context, unit_id):\n        ''' Initializes the datastores\n\n        :param context: The underlying context to operate with\n        :param unit_id: The slave that this context will contact\n        '''\n        self.context = context\n        self.unit_id = unit_id\n\n    def reset(self):\n        ''' Resets all the datastores to their default values '''\n        raise NotImplementedException()\n\n    def validate(self, fx, address, count=1):\n        ''' Validates the request to make sure it is in range\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param count: The number of values to test\n        :returns: True if the request in within range, False otherwise\n        '''\n        _logger.debug(\"validate[%d] %d:%d\" % (fx, address, count))\n        result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)\n        return result.function_code < 0x80\n\n    def getValues(self, fx, address, count=1):\n        ''' Validates the request to make sure it is in range\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param count: The number of values to retrieve\n        :returns: The requested values from a:a+c\n        '''\n        _logger.debug(\"get values[%d] %d:%d\" % (fx, address, count))\n        result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)\n        return self.__extract_result(self.decode(fx), result)\n\n    def setValues(self, fx, address, values):\n        ''' Sets the datastore with the supplied values\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param values: The new values to be set\n        '''\n        _logger.debug(\"set values[%d] %d:%d\" % (fx, address, len(values)))\n        self.context.set_callbacks[self.decode(fx)](address, values, self.unit_id)\n\n    def __str__(self):\n        ''' Returns a string representation of the context\n\n        :returns: A string representation of the context\n        '''\n        return \"Remote Single Slave Context(%s)\" % self.unit_id\n\n    def __extract_result(self, fx, result):\n        ''' A helper method to extract the values out of\n        a response. The future api should make the result\n        consistent so we can just call `result.getValues()`.\n\n        :param fx: The function to call\n        :param result: The resulting data\n        '''\n        if result.function_code < 0x80:\n            if fx in ['d', 'c']: return result.bits\n            if fx in ['h', 'i']: return result.registers\n        else: return result\n\n#---------------------------------------------------------------------------#\n# Server Context\n#---------------------------------------------------------------------------#\n# Think of this as simply a dictionary of { unit_id: client(req, unit_id) }\n#---------------------------------------------------------------------------#\n\nclass RemoteServerContext(object):\n    ''' This is a remote server context that allows one\n    to create a server context backed by a single client that\n    may be attached to many slave units. This can be used to\n    effectively create a modbus forwarding server.\n    '''\n\n    def __init__(self, client):\n        ''' Initializes the datastores\n\n        :param client: The client to retrieve values with\n        '''\n        self.get_callbacks = {\n            'd': lambda a, c, s: client.read_discrete_inputs(a, c, s),\n            'c': lambda a, c, s: client.read_coils(a, c, s),\n            'h': lambda a, c, s: client.read_holding_registers(a, c, s),\n            'i': lambda a, c, s: client.read_input_registers(a, c, s),\n        }\n        self.set_callbacks = {\n            'd': lambda a, v, s: client.write_coils(a, v, s),\n            'c': lambda a, v, s: client.write_coils(a, v, s),\n            'h': lambda a, v, s: client.write_registers(a, v, s),\n            'i': lambda a, v, s: client.write_registers(a, v, s),\n        }\n        self.slaves = {} # simply a cache\n\n    def __str__(self):\n        ''' Returns a string representation of the context\n\n        :returns: A string representation of the context\n        '''\n        return \"Remote Server Context(%s)\" % self._client\n\n    def __iter__(self):\n        ''' Iterater over the current collection of slave\n        contexts.\n\n        :returns: An iterator over the slave contexts\n        '''\n        # note, this may not include all slaves\n        return self.__slaves.iteritems()\n\n    def __contains__(self, slave):\n        ''' Check if the given slave is in this list\n\n        :param slave: slave The slave to check for existance\n        :returns: True if the slave exists, False otherwise\n        '''\n        # we don't want to check the cache here as the\n        # slave may not exist yet or may not exist any\n        # more. The best thing to do is try and fail.\n        return True\n\n    def __setitem__(self, slave, context):\n        ''' Used to set a new slave context\n\n        :param slave: The slave context to set\n        :param context: The new context to set for this slave\n        '''\n        raise NotImplementedException() # doesn't make sense here\n\n    def __delitem__(self, slave):\n        ''' Wrapper used to access the slave context\n\n        :param slave: The slave context to remove\n        '''\n        raise NotImplementedException() # doesn't make sense here\n\n    def __getitem__(self, slave):\n        ''' Used to get access to a slave context\n\n        :param slave: The slave context to get\n        :returns: The requested slave context\n        '''\n        if slave not in self.slaves:\n            self.slaves[slave] = RemoteSingleSlaveContext(self, slave)\n        return self.slaves[slave]\n", "path": "examples/contrib/remote_server_context.py"}], "after_files": [{"content": "'''\nAlthough there is a remote server context already in the main library,\nit works under the assumption that users would have a server context\nof the following form::\n\n    server_context = {\n        0x00: client('host1.something.com'),\n        0x01: client('host2.something.com'),\n        0x02: client('host3.something.com')\n    }\n\nThis example is how to create a server context where the client is\npointing to the same host, but the requested slave id is used as the\nslave for the client::\n\n    server_context = {\n        0x00: client('host1.something.com', 0x00),\n        0x01: client('host1.something.com', 0x01),\n        0x02: client('host1.something.com', 0x02)\n    }\n'''\nfrom pymodbus.exceptions import NotImplementedException\nfrom pymodbus.interfaces import IModbusSlaveContext\n\n#---------------------------------------------------------------------------#\n# Logging\n#---------------------------------------------------------------------------#\n\nimport logging\n_logger = logging.getLogger(__name__)\n\n#---------------------------------------------------------------------------#\n# Slave Context\n#---------------------------------------------------------------------------#\n# Basically we create a new slave context for the given slave identifier so\n# that this slave context will only make requests to that slave with the\n# client that the server is maintaining.\n#---------------------------------------------------------------------------#\n\nclass RemoteSingleSlaveContext(IModbusSlaveContext):\n    ''' This is a remote server context that allows one\n    to create a server context backed by a single client that\n    may be attached to many slave units. This can be used to\n    effectively create a modbus forwarding server.\n    '''\n\n    def __init__(self, context, unit_id):\n        ''' Initializes the datastores\n\n        :param context: The underlying context to operate with\n        :param unit_id: The slave that this context will contact\n        '''\n        self.context = context\n        self.unit_id = unit_id\n\n    def reset(self):\n        ''' Resets all the datastores to their default values '''\n        raise NotImplementedException()\n\n    def validate(self, fx, address, count=1):\n        ''' Validates the request to make sure it is in range\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param count: The number of values to test\n        :returns: True if the request in within range, False otherwise\n        '''\n        _logger.debug(\"validate[%d] %d:%d\" % (fx, address, count))\n        result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)\n        return result.function_code < 0x80\n\n    def getValues(self, fx, address, count=1):\n        ''' Validates the request to make sure it is in range\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param count: The number of values to retrieve\n        :returns: The requested values from a:a+c\n        '''\n        _logger.debug(\"get values[%d] %d:%d\" % (fx, address, count))\n        result = self.context.get_callbacks[self.decode(fx)](address, count, self.unit_id)\n        return self.__extract_result(self.decode(fx), result)\n\n    def setValues(self, fx, address, values):\n        ''' Sets the datastore with the supplied values\n\n        :param fx: The function we are working with\n        :param address: The starting address\n        :param values: The new values to be set\n        '''\n        _logger.debug(\"set values[%d] %d:%d\" % (fx, address, len(values)))\n        self.context.set_callbacks[self.decode(fx)](address, values, self.unit_id)\n\n    def __str__(self):\n        ''' Returns a string representation of the context\n\n        :returns: A string representation of the context\n        '''\n        return \"Remote Single Slave Context(%s)\" % self.unit_id\n\n    def __extract_result(self, fx, result):\n        ''' A helper method to extract the values out of\n        a response. The future api should make the result\n        consistent so we can just call `result.getValues()`.\n\n        :param fx: The function to call\n        :param result: The resulting data\n        '''\n        if result.function_code < 0x80:\n            if fx in ['d', 'c']: return result.bits\n            if fx in ['h', 'i']: return result.registers\n        else: return result\n\n#---------------------------------------------------------------------------#\n# Server Context\n#---------------------------------------------------------------------------#\n# Think of this as simply a dictionary of { unit_id: client(req, unit_id) }\n#---------------------------------------------------------------------------#\n\nclass RemoteServerContext(object):\n    ''' This is a remote server context that allows one\n    to create a server context backed by a single client that\n    may be attached to many slave units. This can be used to\n    effectively create a modbus forwarding server.\n    '''\n\n    def __init__(self, client):\n        ''' Initializes the datastores\n\n        :param client: The client to retrieve values with\n        '''\n        self.get_callbacks = {\n            'd': lambda a, c, s: client.read_discrete_inputs(a, c, s),\n            'c': lambda a, c, s: client.read_coils(a, c, s),\n            'h': lambda a, c, s: client.read_holding_registers(a, c, s),\n            'i': lambda a, c, s: client.read_input_registers(a, c, s),\n        }\n        self.set_callbacks = {\n            'd': lambda a, v, s: client.write_coils(a, v, s),\n            'c': lambda a, v, s: client.write_coils(a, v, s),\n            'h': lambda a, v, s: client.write_registers(a, v, s),\n            'i': lambda a, v, s: client.write_registers(a, v, s),\n        }\n        self._client = client\n        self.slaves = {} # simply a cache\n\n    def __str__(self):\n        ''' Returns a string representation of the context\n\n        :returns: A string representation of the context\n        '''\n        return \"Remote Server Context(%s)\" % self._client\n\n    def __iter__(self):\n        ''' Iterater over the current collection of slave\n        contexts.\n\n        :returns: An iterator over the slave contexts\n        '''\n        # note, this may not include all slaves\n        return iter(self.slaves.items())\n\n    def __contains__(self, slave):\n        ''' Check if the given slave is in this list\n\n        :param slave: slave The slave to check for existance\n        :returns: True if the slave exists, False otherwise\n        '''\n        # we don't want to check the cache here as the\n        # slave may not exist yet or may not exist any\n        # more. The best thing to do is try and fail.\n        return True\n\n    def __setitem__(self, slave, context):\n        ''' Used to set a new slave context\n\n        :param slave: The slave context to set\n        :param context: The new context to set for this slave\n        '''\n        raise NotImplementedException() # doesn't make sense here\n\n    def __delitem__(self, slave):\n        ''' Wrapper used to access the slave context\n\n        :param slave: The slave context to remove\n        '''\n        raise NotImplementedException() # doesn't make sense here\n\n    def __getitem__(self, slave):\n        ''' Used to get access to a slave context\n\n        :param slave: The slave context to get\n        :returns: The requested slave context\n        '''\n        if slave not in self.slaves:\n            self.slaves[slave] = RemoteSingleSlaveContext(self, slave)\n        return self.slaves[slave]\n", "path": "examples/contrib/remote_server_context.py"}]}