removing unused line

Looks like a copy-paste error left an extra line around.

IPython/external/mathjax.py

@@ -1,238 +1,237 b''
 #!/usr/bin/python
 """Utility function for installing MathJax javascript library into
 your IPython nbextensions directory, for offline use.
 
  Authors:
 
  * Min RK
  * Mark Sienkiewicz
  * Matthias Bussonnier
 
 To download and install MathJax:
 
 From Python:
 
     >>> from IPython.external.mathjax import install_mathjax
     >>> install_mathjax()
 
 From the command line:
 
     $ python -m IPython.external.mathjax
 
 To a specific location:
 
     $ python -m IPython.external.mathjax -i /usr/share/
 
 will install mathjax to /usr/share/mathjax
 
 To install MathJax from a file you have already downloaded:
 
     $ python -m IPython.external.mathjax mathjax-xxx.tar.gz
     $ python -m IPython.external.mathjax mathjax-xxx.zip
 
 It will not install MathJax if it is already there.  Use -r to
 replace the existing copy of MathJax.
 
 To find the directory where IPython would like MathJax installed:
 
     $ python -m IPython.external.mathjax -d
 
 """
 from __future__ import print_function
 
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import argparse
 import os
 import shutil
 import sys
 import tarfile
 import zipfile
 
 from IPython.utils.path import get_ipython_dir
 
 try:
     from urllib.request import urlopen # Py 3
 except ImportError:
     from urllib2 import urlopen
 
 #-----------------------------------------------------------------------------
 #
 #-----------------------------------------------------------------------------
 
 # Where mathjax will be installed
 
 nbextensions = os.path.join(get_ipython_dir(), 'nbextensions')
 default_dest = os.path.join(nbextensions, 'mathjax')
 
 # Test for access to install mathjax
 
 def prepare_dest(dest, replace=False):
     """prepare the destination folder for mathjax install
     
     Returns False if mathjax appears to already be installed and there is nothing to do,
     True otherwise.
     """
     
     parent = os.path.abspath(os.path.join(dest, os.path.pardir))
     if not os.path.exists(parent):
         os.makedirs(parent)
     
     if os.path.exists(dest):
         if replace:
             print("removing existing MathJax at %s" % dest)
             shutil.rmtree(dest)
             return True
         else:
             mathjax_js = os.path.join(dest, 'MathJax.js')
             if not os.path.exists(mathjax_js):
                 raise IOError("%s exists, but does not contain MathJax.js" % dest)
             print("%s already exists" % mathjax_js)
             return False
     else:
         return True
 
 
 def extract_tar(fd, dest):
     """extract a tarball from filelike `fd` to destination `dest`"""
     # use 'r|gz' stream mode, because socket file-like objects can't seek:
     tar = tarfile.open(fileobj=fd, mode='r|gz')
 
     # The first entry in the archive is the top-level dir
     topdir = tar.firstmember.path
 
     # extract the archive (contains a single directory) to the destination directory
     parent = os.path.abspath(os.path.join(dest, os.path.pardir))
     tar.extractall(parent)
 
     # it will be mathjax-MathJax-<sha>, rename to just mathjax
     os.rename(os.path.join(parent, topdir), dest)
 
 
 def extract_zip(fd, dest):
     """extract a zip file from filelike `fd` to destination `dest`"""
     z = zipfile.ZipFile(fd, 'r')
 
     # The first entry in the archive is the top-level dir
     topdir = z.namelist()[0]
 
     # extract the archive (contains a single directory) to the static/ directory
     parent = os.path.abspath(os.path.join(dest, os.path.pardir))
     z.extractall(parent)
 
     # it will be mathjax-MathJax-<sha>, rename to just mathjax
-    d = os.path.join(parent, topdir)
     os.rename(os.path.join(parent, topdir), dest)
 
 
 def install_mathjax(tag='2.4.0', dest=default_dest, replace=False, file=None, extractor=extract_tar):
     """Download and/or install MathJax for offline use.
 
     This will install mathjax to the nbextensions dir in your IPYTHONDIR.
 
     MathJax is a ~15MB download, and ~150MB installed.
 
     Parameters
     ----------
 
     replace : bool [False]
         Whether to remove and replace an existing install.
     dest : str [IPYTHONDIR/nbextensions/mathjax]
         Where to install mathjax
     tag : str ['2.4.0']
         Which tag to download. Default is '2.4.0', the current stable release,
         but alternatives include 'v1.1a' and 'master'.
     file : file like object [ defualt to content of https://github.com/mathjax/MathJax/tarball/#{tag}]
         File handle from which to untar/unzip/... mathjax
     extractor : function
         Method to use to untar/unzip/... `file`
     """
     try:
         anything_to_do = prepare_dest(dest, replace)
     except OSError as e:
         print("ERROR %s, require write access to %s" % (e, dest))
         return 1
     else:
         if not anything_to_do:
             return 0
 
     if file is None:
         # download mathjax
         mathjax_url = "https://github.com/mathjax/MathJax/archive/%s.tar.gz" %tag
         print("Downloading mathjax source from %s" % mathjax_url)
         response = urlopen(mathjax_url)
         file = response.fp
 
     print("Extracting to %s" % dest)
     extractor(file, dest)
     return 0
 
 
 def main():
     parser = argparse.ArgumentParser(
             description="""Install mathjax from internet or local archive""",
     )
 
     parser.add_argument(
             '-i',
             '--install-dir',
             default=nbextensions,
             help='custom installation directory. Mathjax will be installed in here/mathjax')
 
     parser.add_argument(
             '-d',
             '--print-dest',
             action='store_true',
             help='print where mathjax would be installed and exit')
     parser.add_argument(
             '-r',
             '--replace',
             action='store_true',
             help='Whether to replace current mathjax if it already exists')
     parser.add_argument('filename',
             help="the local tar/zip-ball filename containing mathjax",
             nargs='?',
             metavar='filename')
 
     pargs = parser.parse_args()
 
     dest = os.path.join(pargs.install_dir, 'mathjax')
 
     if pargs.print_dest:
         print(dest)
         return
 
     # remove/replace existing mathjax?
     replace = pargs.replace
 
     # do it
     if pargs.filename:
         fname = pargs.filename
 
         # automatically detect zip/tar - could do something based
         # on file content, but really not cost-effective here.
         if fname.endswith('.zip'):
             extractor = extract_zip
         else :
             extractor = extract_tar
         # do it
         return install_mathjax(file=open(fname, "rb"), replace=replace, extractor=extractor, dest=dest)
     else:
         return install_mathjax(replace=replace, dest=dest)
 
 
 if __name__ == '__main__' :
     sys.exit(main())
 
 __all__ = ['install_mathjax', 'main', 'default_dest']