We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
nikola bootswatch_theme paper installs slate
I seem to be getting an issue when I try to install the [paper](https://bootswatch.com/paper/) theme from bootswatch by running `nikola bootswatch_theme paper`, it seems to install slate instead. 

The output is as follows:

```
$ nikola bootswatch_theme paper
[2015-04-16T00:24:34Z] WARNING: Nikola: Your BASE_URL doesn't end in / -- adding it, but please fix it in your config file!
[2015-04-16T00:24:34Z] WARNING: Nikola: In order to USE_BUNDLES, you must install the "webassets" Python package.
[2015-04-16T00:24:34Z] WARNING: bundles: Setting USE_BUNDLES to False.
[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Creating 'custom' theme from 'slate' and 'bootstrap3'
[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Downloading: http://bootswatch.com/slate/bootstrap.min.css
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): bootswatch.com
[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Downloading: http://bootswatch.com/slate/bootstrap.css
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): bootswatch.com
[2015-04-16T00:24:34Z] NOTICE: bootswatch_theme: Theme created.  Change the THEME setting to "custom" to use it.
```

If you notice it says `Creating 'custom' theme from 'slate' and 'bootstrap3'` and installs slate instead. 

This is on osx but I was able replicate it on my friends box as well which is running fedora.


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `nikola/plugins/command/bootswatch_theme.py`
Content:
```
1 # -*- coding: utf-8 -*-
2 
3 # Copyright © 2012-2015 Roberto Alsina and others.
4 
5 # Permission is hereby granted, free of charge, to any
6 # person obtaining a copy of this software and associated
7 # documentation files (the "Software"), to deal in the
8 # Software without restriction, including without limitation
9 # the rights to use, copy, modify, merge, publish,
10 # distribute, sublicense, and/or sell copies of the
11 # Software, and to permit persons to whom the Software is
12 # furnished to do so, subject to the following conditions:
13 #
14 # The above copyright notice and this permission notice
15 # shall be included in all copies or substantial portions of
16 # the Software.
17 #
18 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
19 # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
20 # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
21 # PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
22 # OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
23 # OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 # OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
25 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 
27 from __future__ import print_function
28 import os
29 
30 try:
31     import requests
32 except ImportError:
33     requests = None  # NOQA
34 
35 from nikola.plugin_categories import Command
36 from nikola import utils
37 
38 LOGGER = utils.get_logger('bootswatch_theme', utils.STDERR_HANDLER)
39 
40 
41 class CommandBootswatchTheme(Command):
42     """Given a swatch name from bootswatch.com and a parent theme, creates a custom theme."""
43 
44     name = "bootswatch_theme"
45     doc_usage = "[options]"
46     doc_purpose = "given a swatch name from bootswatch.com and a parent theme, creates a custom"\
47         " theme"
48     cmd_options = [
49         {
50             'name': 'name',
51             'short': 'n',
52             'long': 'name',
53             'default': 'custom',
54             'type': str,
55             'help': 'New theme name (default: custom)',
56         },
57         {
58             'name': 'swatch',
59             'short': 's',
60             'default': 'slate',
61             'type': str,
62             'help': 'Name of the swatch from bootswatch.com.'
63         },
64         {
65             'name': 'parent',
66             'short': 'p',
67             'long': 'parent',
68             'default': 'bootstrap3',
69             'help': 'Parent theme name (default: bootstrap3)',
70         },
71     ]
72 
73     def _execute(self, options, args):
74         """Given a swatch name and a parent theme, creates a custom theme."""
75         if requests is None:
76             utils.req_missing(['requests'], 'install Bootswatch themes')
77 
78         name = options['name']
79         swatch = options['swatch']
80         parent = options['parent']
81         version = ''
82 
83         # See if we need bootswatch for bootstrap v2 or v3
84         themes = utils.get_theme_chain(parent)
85         if 'bootstrap3' not in themes and 'bootstrap3-jinja' not in themes:
86             version = '2'
87         elif 'bootstrap' not in themes and 'bootstrap-jinja' not in themes:
88             LOGGER.warn('"bootswatch_theme" only makes sense for themes that use bootstrap')
89         elif 'bootstrap3-gradients' in themes or 'bootstrap3-gradients-jinja' in themes:
90             LOGGER.warn('"bootswatch_theme" doesn\'t work well with the bootstrap3-gradients family')
91 
92         LOGGER.info("Creating '{0}' theme from '{1}' and '{2}'".format(name, swatch, parent))
93         utils.makedirs(os.path.join('themes', name, 'assets', 'css'))
94         for fname in ('bootstrap.min.css', 'bootstrap.css'):
95             url = 'http://bootswatch.com'
96             if version:
97                 url += '/' + version
98             url = '/'.join((url, swatch, fname))
99             LOGGER.info("Downloading: " + url)
100             data = requests.get(url).text
101             with open(os.path.join('themes', name, 'assets', 'css', fname),
102                       'wb+') as output:
103                 output.write(data.encode('utf-8'))
104 
105         with open(os.path.join('themes', name, 'parent'), 'wb+') as output:
106             output.write(parent.encode('utf-8'))
107         LOGGER.notice('Theme created.  Change the THEME setting to "{0}" to use it.'.format(name))
108
```
--- 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/nikola/plugins/command/bootswatch_theme.py b/nikola/plugins/command/bootswatch_theme.py
--- a/nikola/plugins/command/bootswatch_theme.py
+++ b/nikola/plugins/command/bootswatch_theme.py
@@ -26,6 +26,7 @@
 
 from __future__ import print_function
 import os
+import sys
 
 try:
     import requests
@@ -57,7 +58,7 @@
         {
             'name': 'swatch',
             'short': 's',
-            'default': 'slate',
+            'default': '',
             'type': str,
             'help': 'Name of the swatch from bootswatch.com.'
         },
@@ -77,6 +78,9 @@
 
         name = options['name']
         swatch = options['swatch']
+        if not swatch:
+            LOGGER.error('The -s option is mandatory')
+            sys.exit(1)
         parent = options['parent']
         version = ''

{"golden_diff": "diff --git a/nikola/plugins/command/bootswatch_theme.py b/nikola/plugins/command/bootswatch_theme.py\n--- a/nikola/plugins/command/bootswatch_theme.py\n+++ b/nikola/plugins/command/bootswatch_theme.py\n@@ -26,6 +26,7 @@\n \n from __future__ import print_function\n import os\n+import sys\n \n try:\n     import requests\n@@ -57,7 +58,7 @@\n         {\n             'name': 'swatch',\n             'short': 's',\n-            'default': 'slate',\n+            'default': '',\n             'type': str,\n             'help': 'Name of the swatch from bootswatch.com.'\n         },\n@@ -77,6 +78,9 @@\n \n         name = options['name']\n         swatch = options['swatch']\n+        if not swatch:\n+            LOGGER.error('The -s option is mandatory')\n+            sys.exit(1)\n         parent = options['parent']\n         version = ''\n", "issue": "nikola bootswatch_theme paper installs slate\nI seem to be getting an issue when I try to install the [paper](https://bootswatch.com/paper/) theme from bootswatch by running `nikola bootswatch_theme paper`, it seems to install slate instead. \n\nThe output is as follows:\n\n```\n$ nikola bootswatch_theme paper\n[2015-04-16T00:24:34Z] WARNING: Nikola: Your BASE_URL doesn't end in / -- adding it, but please fix it in your config file!\n[2015-04-16T00:24:34Z] WARNING: Nikola: In order to USE_BUNDLES, you must install the \"webassets\" Python package.\n[2015-04-16T00:24:34Z] WARNING: bundles: Setting USE_BUNDLES to False.\n[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Creating 'custom' theme from 'slate' and 'bootstrap3'\n[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Downloading: http://bootswatch.com/slate/bootstrap.min.css\nINFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): bootswatch.com\n[2015-04-16T00:24:34Z] INFO: bootswatch_theme: Downloading: http://bootswatch.com/slate/bootstrap.css\nINFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): bootswatch.com\n[2015-04-16T00:24:34Z] NOTICE: bootswatch_theme: Theme created.  Change the THEME setting to \"custom\" to use it.\n```\n\nIf you notice it says `Creating 'custom' theme from 'slate' and 'bootstrap3'` and installs slate instead. \n\nThis is on osx but I was able replicate it on my friends box as well which is running fedora.\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n\n# Copyright \u00a9 2012-2015 Roberto Alsina and others.\n\n# Permission is hereby granted, free of charge, to any\n# person obtaining a copy of this software and associated\n# documentation files (the \"Software\"), to deal in the\n# Software without restriction, including without limitation\n# the rights to use, copy, modify, merge, publish,\n# distribute, sublicense, and/or sell copies of the\n# Software, and to permit persons to whom the Software is\n# furnished to do so, subject to the following conditions:\n#\n# The above copyright notice and this permission notice\n# shall be included in all copies or substantial portions of\n# the Software.\n#\n# THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY\n# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE\n# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR\n# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS\n# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR\n# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR\n# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE\n# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\n\nfrom __future__ import print_function\nimport os\n\ntry:\n    import requests\nexcept ImportError:\n    requests = None  # NOQA\n\nfrom nikola.plugin_categories import Command\nfrom nikola import utils\n\nLOGGER = utils.get_logger('bootswatch_theme', utils.STDERR_HANDLER)\n\n\nclass CommandBootswatchTheme(Command):\n    \"\"\"Given a swatch name from bootswatch.com and a parent theme, creates a custom theme.\"\"\"\n\n    name = \"bootswatch_theme\"\n    doc_usage = \"[options]\"\n    doc_purpose = \"given a swatch name from bootswatch.com and a parent theme, creates a custom\"\\\n        \" theme\"\n    cmd_options = [\n        {\n            'name': 'name',\n            'short': 'n',\n            'long': 'name',\n            'default': 'custom',\n            'type': str,\n            'help': 'New theme name (default: custom)',\n        },\n        {\n            'name': 'swatch',\n            'short': 's',\n            'default': 'slate',\n            'type': str,\n            'help': 'Name of the swatch from bootswatch.com.'\n        },\n        {\n            'name': 'parent',\n            'short': 'p',\n            'long': 'parent',\n            'default': 'bootstrap3',\n            'help': 'Parent theme name (default: bootstrap3)',\n        },\n    ]\n\n    def _execute(self, options, args):\n        \"\"\"Given a swatch name and a parent theme, creates a custom theme.\"\"\"\n        if requests is None:\n            utils.req_missing(['requests'], 'install Bootswatch themes')\n\n        name = options['name']\n        swatch = options['swatch']\n        parent = options['parent']\n        version = ''\n\n        # See if we need bootswatch for bootstrap v2 or v3\n        themes = utils.get_theme_chain(parent)\n        if 'bootstrap3' not in themes and 'bootstrap3-jinja' not in themes:\n            version = '2'\n        elif 'bootstrap' not in themes and 'bootstrap-jinja' not in themes:\n            LOGGER.warn('\"bootswatch_theme\" only makes sense for themes that use bootstrap')\n        elif 'bootstrap3-gradients' in themes or 'bootstrap3-gradients-jinja' in themes:\n            LOGGER.warn('\"bootswatch_theme\" doesn\\'t work well with the bootstrap3-gradients family')\n\n        LOGGER.info(\"Creating '{0}' theme from '{1}' and '{2}'\".format(name, swatch, parent))\n        utils.makedirs(os.path.join('themes', name, 'assets', 'css'))\n        for fname in ('bootstrap.min.css', 'bootstrap.css'):\n            url = 'http://bootswatch.com'\n            if version:\n                url += '/' + version\n            url = '/'.join((url, swatch, fname))\n            LOGGER.info(\"Downloading: \" + url)\n            data = requests.get(url).text\n            with open(os.path.join('themes', name, 'assets', 'css', fname),\n                      'wb+') as output:\n                output.write(data.encode('utf-8'))\n\n        with open(os.path.join('themes', name, 'parent'), 'wb+') as output:\n            output.write(parent.encode('utf-8'))\n        LOGGER.notice('Theme created.  Change the THEME setting to \"{0}\" to use it.'.format(name))\n", "path": "nikola/plugins/command/bootswatch_theme.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n\n# Copyright \u00a9 2012-2015 Roberto Alsina and others.\n\n# Permission is hereby granted, free of charge, to any\n# person obtaining a copy of this software and associated\n# documentation files (the \"Software\"), to deal in the\n# Software without restriction, including without limitation\n# the rights to use, copy, modify, merge, publish,\n# distribute, sublicense, and/or sell copies of the\n# Software, and to permit persons to whom the Software is\n# furnished to do so, subject to the following conditions:\n#\n# The above copyright notice and this permission notice\n# shall be included in all copies or substantial portions of\n# the Software.\n#\n# THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY\n# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE\n# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR\n# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS\n# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR\n# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR\n# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE\n# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\n\nfrom __future__ import print_function\nimport os\nimport sys\n\ntry:\n    import requests\nexcept ImportError:\n    requests = None  # NOQA\n\nfrom nikola.plugin_categories import Command\nfrom nikola import utils\n\nLOGGER = utils.get_logger('bootswatch_theme', utils.STDERR_HANDLER)\n\n\nclass CommandBootswatchTheme(Command):\n    \"\"\"Given a swatch name from bootswatch.com and a parent theme, creates a custom theme.\"\"\"\n\n    name = \"bootswatch_theme\"\n    doc_usage = \"[options]\"\n    doc_purpose = \"given a swatch name from bootswatch.com and a parent theme, creates a custom\"\\\n        \" theme\"\n    cmd_options = [\n        {\n            'name': 'name',\n            'short': 'n',\n            'long': 'name',\n            'default': 'custom',\n            'type': str,\n            'help': 'New theme name (default: custom)',\n        },\n        {\n            'name': 'swatch',\n            'short': 's',\n            'default': '',\n            'type': str,\n            'help': 'Name of the swatch from bootswatch.com.'\n        },\n        {\n            'name': 'parent',\n            'short': 'p',\n            'long': 'parent',\n            'default': 'bootstrap3',\n            'help': 'Parent theme name (default: bootstrap3)',\n        },\n    ]\n\n    def _execute(self, options, args):\n        \"\"\"Given a swatch name and a parent theme, creates a custom theme.\"\"\"\n        if requests is None:\n            utils.req_missing(['requests'], 'install Bootswatch themes')\n\n        name = options['name']\n        swatch = options['swatch']\n        if not swatch:\n            LOGGER.error('The -s option is mandatory')\n            sys.exit(1)\n        parent = options['parent']\n        version = ''\n\n        # See if we need bootswatch for bootstrap v2 or v3\n        themes = utils.get_theme_chain(parent)\n        if 'bootstrap3' not in themes and 'bootstrap3-jinja' not in themes:\n            version = '2'\n        elif 'bootstrap' not in themes and 'bootstrap-jinja' not in themes:\n            LOGGER.warn('\"bootswatch_theme\" only makes sense for themes that use bootstrap')\n        elif 'bootstrap3-gradients' in themes or 'bootstrap3-gradients-jinja' in themes:\n            LOGGER.warn('\"bootswatch_theme\" doesn\\'t work well with the bootstrap3-gradients family')\n\n        LOGGER.info(\"Creating '{0}' theme from '{1}' and '{2}'\".format(name, swatch, parent))\n        utils.makedirs(os.path.join('themes', name, 'assets', 'css'))\n        for fname in ('bootstrap.min.css', 'bootstrap.css'):\n            url = 'http://bootswatch.com'\n            if version:\n                url += '/' + version\n            url = '/'.join((url, swatch, fname))\n            LOGGER.info(\"Downloading: \" + url)\n            data = requests.get(url).text\n            with open(os.path.join('themes', name, 'assets', 'css', fname),\n                      'wb+') as output:\n                output.write(data.encode('utf-8'))\n\n        with open(os.path.join('themes', name, 'parent'), 'wb+') as output:\n            output.write(parent.encode('utf-8'))\n        LOGGER.notice('Theme created.  Change the THEME setting to \"{0}\" to use it.'.format(name))\n", "path": "nikola/plugins/command/bootswatch_theme.py"}]}