title: Error while downloading the requirements using pip install (setup command: use_2to3 is invalid.)
body: <p>version pip 21.2.4
  python 3.6</p>
  <p>The command:</p>
  <pre><code>pip install -r  requirements.txt
  </code></pre>
  <p>The content of my <code>requirements.txt</code>:</p>
  <pre><code>mongoengine==0.19.1
  numpy==1.16.2
  pylint
  pandas==1.1.5
  fawkes
  </code></pre>
  <p>The command is failing with this error</p>
  <pre><code>ERROR: Command errored out with exit status 1:
       command: /Users/*/Desktop/ml/*/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '&quot;'&quot;'/private/var/folders/kn/0y92g7x55qs7c42tln4gwhtm0000gp/T/pip-install-soh30mel/mongoengine_89e68f8427244f1bb3215b22f77a619c/setup.py'&quot;'&quot;'; __file__='&quot;'&quot;'/private/var/folders/kn/0y92g7x55qs7c42tln4gwhtm0000gp/T/pip-install-soh30mel/mongoengine_89e68f8427244f1bb3215b22f77a619c/setup.py'&quot;'&quot;';f = getattr(tokenize, '&quot;'&quot;'open'&quot;'&quot;', open)(__file__) if os.path.exists(__file__) else io.StringIO('&quot;'&quot;'from setuptools import setup; setup()'&quot;'&quot;');code = f.read().replace('&quot;'&quot;'\r\n'&quot;'&quot;', '&quot;'&quot;'\n'&quot;'&quot;');f.close();exec(compile(code, __file__, '&quot;'&quot;'exec'&quot;'&quot;'))' egg_info --egg-base /private/var/folders/kn/0y92g7x55qs7c42tln4gwhtm0000gp/T/pip-pip-egg-info-97994d6e
           cwd: /private/var/folders/kn/0y92g7x55qs7c42tln4gwhtm0000gp/T/pip-install-soh30mel/mongoengine_89e68f8427244f1bb3215b22f77a619c/
      Complete output (1 lines):
      error in mongoengine setup command: use_2to3 is invalid.
      ----------------------------------------
  WARNING: Discarding https://*/pypi/packages/mongoengine-0.19.1.tar.gz#md5=68e613009f6466239158821a102ac084 (from https://*/pypi/simple/mongoengine/). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
  ERROR: Could not find a version that satisfies the requirement mongoengine==0.19.1 (from versions: 0.15.0, 0.19.1)
  ERROR: No matching distribution found for mongoengine==0.19.1
  </code></pre>