prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Default OPTIONS responder does not set Content-Length to "0"
  Per RFC 7231:
  
  > A server MUST generate a Content-Length field with a value of "0" if no payload body is to be sent in the response.
  
  
  </issue>
  <code>
  [start of falcon/responders.py]
  1 # Copyright 2013 by Rackspace Hosting, Inc.
  2 #
  3 # Licensed under the Apache License, Version 2.0 (the "License");
  4 # you may not use this file except in compliance with the License.
  5 # You may obtain a copy of the License at
  6 #
  7 #    http://www.apache.org/licenses/LICENSE-2.0
  8 #
  9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14 
  15 """Default responder implementations."""
  16 
  17 from falcon.errors import HTTPBadRequest
  18 from falcon.errors import HTTPMethodNotAllowed
  19 from falcon.errors import HTTPNotFound
  20 from falcon.status_codes import HTTP_204
  21 
  22 
  23 def path_not_found(req, resp, **kwargs):
  24     """Raise 404 HTTPNotFound error"""
  25     raise HTTPNotFound()
  26 
  27 
  28 def bad_request(req, resp, **kwargs):
  29     """Raise 400 HTTPBadRequest error"""
  30     raise HTTPBadRequest('Bad request', 'Invalid HTTP method')
  31 
  32 
  33 def create_method_not_allowed(allowed_methods):
  34     """Creates a responder for "405 Method Not Allowed"
  35 
  36     Args:
  37         allowed_methods: A list of HTTP methods (uppercase) that should be
  38             returned in the Allow header.
  39 
  40     """
  41     def method_not_allowed(req, resp, **kwargs):
  42         """Raise 405 HTTPMethodNotAllowed error"""
  43         raise HTTPMethodNotAllowed(allowed_methods)
  44 
  45     return method_not_allowed
  46 
  47 
  48 def create_default_options(allowed_methods):
  49     """Creates a default responder for the OPTIONS method
  50 
  51     Args:
  52         allowed_methods: A list of HTTP methods (uppercase) that should be
  53             returned in the Allow header.
  54 
  55     """
  56     allowed = ', '.join(allowed_methods)
  57 
  58     def on_options(req, resp, **kwargs):
  59         resp.status = HTTP_204
  60         resp.set_header('Allow', allowed)
  61         resp.set_header('Content-Length', '0')
  62 
  63     return on_options
  64
  [end of falcon/responders.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/falcon/responders.py b/falcon/responders.py
  --- a/falcon/responders.py
  +++ b/falcon/responders.py
  @@ -17,7 +17,7 @@
   from falcon.errors import HTTPBadRequest
   from falcon.errors import HTTPMethodNotAllowed
   from falcon.errors import HTTPNotFound
  -from falcon.status_codes import HTTP_204
  +from falcon.status_codes import HTTP_200
   
   
   def path_not_found(req, resp, **kwargs):
  @@ -56,7 +56,7 @@
       allowed = ', '.join(allowed_methods)
   
       def on_options(req, resp, **kwargs):
  -        resp.status = HTTP_204
  +        resp.status = HTTP_200
           resp.set_header('Allow', allowed)
           resp.set_header('Content-Length', '0')
  
verification_info: {"golden_diff": "diff --git a/falcon/responders.py b/falcon/responders.py\n--- a/falcon/responders.py\n+++ b/falcon/responders.py\n@@ -17,7 +17,7 @@\n from falcon.errors import HTTPBadRequest\n from falcon.errors import HTTPMethodNotAllowed\n from falcon.errors import HTTPNotFound\n-from falcon.status_codes import HTTP_204\n+from falcon.status_codes import HTTP_200\n \n \n def path_not_found(req, resp, **kwargs):\n@@ -56,7 +56,7 @@\n     allowed = ', '.join(allowed_methods)\n \n     def on_options(req, resp, **kwargs):\n-        resp.status = HTTP_204\n+        resp.status = HTTP_200\n         resp.set_header('Allow', allowed)\n         resp.set_header('Content-Length', '0')\n", "issue": "Default OPTIONS responder does not set Content-Length to \"0\"\nPer RFC 7231:\n\n> A server MUST generate a Content-Length field with a value of \"0\" if no payload body is to be sent in the response.\n\n", "before_files": [{"content": "# Copyright 2013 by Rackspace Hosting, Inc.\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#    http://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\n\"\"\"Default responder implementations.\"\"\"\n\nfrom falcon.errors import HTTPBadRequest\nfrom falcon.errors import HTTPMethodNotAllowed\nfrom falcon.errors import HTTPNotFound\nfrom falcon.status_codes import HTTP_204\n\n\ndef path_not_found(req, resp, **kwargs):\n    \"\"\"Raise 404 HTTPNotFound error\"\"\"\n    raise HTTPNotFound()\n\n\ndef bad_request(req, resp, **kwargs):\n    \"\"\"Raise 400 HTTPBadRequest error\"\"\"\n    raise HTTPBadRequest('Bad request', 'Invalid HTTP method')\n\n\ndef create_method_not_allowed(allowed_methods):\n    \"\"\"Creates a responder for \"405 Method Not Allowed\"\n\n    Args:\n        allowed_methods: A list of HTTP methods (uppercase) that should be\n            returned in the Allow header.\n\n    \"\"\"\n    def method_not_allowed(req, resp, **kwargs):\n        \"\"\"Raise 405 HTTPMethodNotAllowed error\"\"\"\n        raise HTTPMethodNotAllowed(allowed_methods)\n\n    return method_not_allowed\n\n\ndef create_default_options(allowed_methods):\n    \"\"\"Creates a default responder for the OPTIONS method\n\n    Args:\n        allowed_methods: A list of HTTP methods (uppercase) that should be\n            returned in the Allow header.\n\n    \"\"\"\n    allowed = ', '.join(allowed_methods)\n\n    def on_options(req, resp, **kwargs):\n        resp.status = HTTP_204\n        resp.set_header('Allow', allowed)\n        resp.set_header('Content-Length', '0')\n\n    return on_options\n", "path": "falcon/responders.py"}]}