title: How to install the latest python module via pip?
body: <p>I can see openbabel 3.0.0 with <code>pip3 search</code>. But when I install it with <code>pip3 install</code>, I get only 2.4.1. Is there anything wrong? How to get the latest version installed? Thanks.</p>
  
  <p>When I try to specify the version, <code>pip</code> does not find it. This is strange given the version on pypi is 3.0.0. <a href="https://pypi.org/project/openbabel/" rel="nofollow noreferrer">https://pypi.org/project/openbabel/</a></p>
  
  <pre><code>$ pip3 install openbabel==3.0.0
  ERROR: Could not find a version that satisfies the requirement openbabel==3.0.0 (from versions: 1.8, 1.8.1, 1.8.2, 1.8.4, 2.4.0, 2.4.1)
  ERROR: No matching distribution found for openbabel==3.0.0
  </code></pre>
  
  <pre><code>$ pip3 search openbabel
  openbabel (3.0.0)  - openbabel: Python interface to the Open Babel chemistry library
  pyOBabel (0.1.1)   - A python binding to openbabel chemical toolbox (http://openbabel.org)
  $ pip3 install openbabel
  Collecting openbabel
    Using cached https://files.pythonhosted.org/packages/9c/30/eb9c3d3d3b86981f6c6a7b8eceb6f4a13b9a12673efbc842b7cebe0ce39a/openbabel-2.4.1.tar.gz
  Installing collected packages: openbabel
      Running setup.py install for openbabel ... error
      ERROR: Command errored out with exit status 1:
       command: /Library/Frameworks/Python.framework/Versions/3.8/bin/python3.8 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/tmp/mktemp/pip-install-6d4dkzh2/openbabel/setup.py'"'"'; __file__='"'"'/private/tmp/mktemp/pip-install-6d4dkzh2/openbabel/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/tmp/mktemp/pip-record-xr3vrvho/install-record.txt --single-version-externally-managed --compile
           cwd: /private/tmp/mktemp/pip-install-6d4dkzh2/openbabel/
      Complete output (64 lines):
      running install
      running build_ext
      Warning: package openbabel-2.0 could not be found by pkg-config.
      Guessing Open Babel location:
      - include_dirs: ['/Library/Frameworks/Python.framework/Versions/3.8/include/python3.8m', '/usr/local/include/openbabel-2.0']
      - library_dirs: ['/usr/local/lib']
      building '_openbabel' extension
      swigging openbabel-python.i to openbabel-python_wrap.cpp
      swig -python -c++ -small -O -templatereduce -naturalvar -I/Library/Frameworks/Python.framework/Versions/3.8/include/python3.8m -I/usr/local/include/openbabel-2.0 -o openbabel-python_wrap.cpp openbabel-python.i
      openbabel-python.i:225: Error: Unable to find 'openbabel/babelconfig.h'
      openbabel-python.i:227: Error: Unable to find 'openbabel/data.h'
      openbabel-python.i:228: Error: Unable to find 'openbabel/rand.h'
      openbabel-python.i:229: Error: Unable to find 'openbabel/obutil.h'
      openbabel-python.i:230: Error: Unable to find 'openbabel/math/vector3.h'
      openbabel-python.i:232: Error: Unable to find 'openbabel/math/matrix3x3.h'
      openbabel-python.i:233: Error: Unable to find 'openbabel/math/transform3d.h'
      openbabel-python.i:234: Error: Unable to find 'openbabel/math/spacegroup.h'
      openbabel-python.i:238: Error: Unable to find 'openbabel/base.h'
      openbabel-python.i:240: Error: Unable to find 'openbabel/generic.h'
      openbabel-python.i:241: Error: Unable to find 'openbabel/griddata.h'
      openbabel-python.i:243: Error: Unable to find 'openbabel/chains.h'
      openbabel-python.i:244: Error: Unable to find 'openbabel/typer.h'
      openbabel-python.i:252: Error: Unable to find 'openbabel/plugin.h'
      openbabel-python.i:257: Error: Unable to find 'openbabel/oberror.h'
      openbabel-python.i:258: Error: Unable to find 'openbabel/format.h'
      openbabel-python.i:259: Error: Unable to find 'openbabel/obconversion.h'
      openbabel-python.i:260: Error: Unable to find 'openbabel/residue.h'
      openbabel-python.i:261: Error: Unable to find 'openbabel/internalcoord.h'
      openbabel-python.i:262: Error: Unable to find 'openbabel/atom.h'
      openbabel-python.i:263: Error: Unable to find 'openbabel/bond.h'
      openbabel-python.i:264: Error: Unable to find 'openbabel/reaction.h'
      openbabel-python.i:282: Error: Unable to find 'openbabel/mol.h'
      openbabel-python.i:289: Error: Unable to find 'openbabel/ring.h'
      openbabel-python.i:290: Error: Unable to find 'openbabel/parsmart.h'
      openbabel-python.i:291: Error: Unable to find 'openbabel/alias.h'
      openbabel-python.i:292: Error: Unable to find 'openbabel/atomclass.h'
      openbabel-python.i:294: Error: Unable to find 'openbabel/fingerprint.h'
      openbabel-python.i:296: Error: Unable to find 'openbabel/descriptor.h'
      openbabel-python.i:301: Error: Unable to find 'openbabel/forcefield.h'
      openbabel-python.i:303: Error: Unable to find 'openbabel/builder.h'
      openbabel-python.i:304: Error: Unable to find 'openbabel/op.h'
      openbabel-python.i:306: Error: Unable to find 'openbabel/chargemodel.h'
      openbabel-python.i:309: Error: Unable to find 'openbabel/phmodel.h'
      openbabel-python.i:310: Error: Unable to find 'openbabel/graphsym.h'
      openbabel-python.i:311: Error: Unable to find 'openbabel/isomorphism.h'
      openbabel-python.i:312: Error: Unable to find 'openbabel/query.h'
      openbabel-python.i:313: Error: Unable to find 'openbabel/canon.h'
      openbabel-python.i:315: Error: Unable to find 'openbabel/stereo/stereo.h'
      openbabel-python.i:318: Error: Unable to find 'openbabel/bitvec.h'
      openbabel-python.i:321: Error: Unable to find 'openbabel/rotor.h'
      openbabel-python.i:323: Error: Unable to find 'openbabel/rotamer.h'
      openbabel-python.i:324: Error: Unable to find 'openbabel/spectrophore.h'
      openbabel-python.i:374: Error: Unable to find 'openbabel/obiter.h'
      stereo.i:1: Error: Unable to find 'openbabel/stereo/tetranonplanar.h'
      stereo.i:2: Error: Unable to find 'openbabel/stereo/tetraplanar.h'
      stereo.i:3: Error: Unable to find 'openbabel/stereo/tetrahedral.h'
      stereo.i:4: Error: Unable to find 'openbabel/stereo/cistrans.h'
      stereo.i:5: Error: Unable to find 'openbabel/stereo/squareplanar.h'
      stereo.i:6: Error: Unable to find 'openbabel/stereo/bindings.h'
  
      Error: SWIG failed. Is Open Babel installed?
      You may need to manually specify the location of Open Babel include and library directories. For example:
        python setup.py build_ext -I/usr/local/include/openbabel-2.0 -L/usr/local/lib
        python setup.py install
      ----------------------------------------
  ERROR: Command errored out with exit status 1: /Library/Frameworks/Python.framework/Versions/3.8/bin/python3.8 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/tmp/mktemp/pip-install-6d4dkzh2/openbabel/setup.py'"'"'; __file__='"'"'/private/tmp/mktemp/pip-install-6d4dkzh2/openbabel/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/tmp/mktemp/pip-record-xr3vrvho/install-record.txt --single-version-externally-managed --compile Check the logs for full command output.
  </code></pre>
  
  <p>open-babel 3.0.0 is installed by homebrew.</p>
  
  <pre><code>$ brew info open-babel
  open-babel: stable 3.0.0 (bottled), HEAD
  Chemical toolbox
  https://openbabel.org
  /usr/local/Cellar/open-babel/3.0.0 (328 files, 19.5MB) *
    Poured from bottle on 2019-11-02 at 02:42:41
  From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/open-babel.rb
  ==&gt; Dependencies
  Build: cmake ✘, pkg-config ✔, rapidjson ✘, swig ✔
  Required: cairo ✔, eigen ✔, python ✘
  ==&gt; Options
  --HEAD
      Install HEAD version
  ``
  </code></pre>