code: def is_python_command(line):
      
  
      if not isinstance(line, six.string_types):
          raise TypeError("Not a valid command to check: {0!r}".format(line))
  
      from pipenv.vendor.pythonfinder.utils import PYTHON_IMPLEMENTATIONS
      is_version = re.match(r'[\d\.]+', line)
      if (line.startswith("python") or is_version or
              any(line.startswith(v) for v in PYTHON_IMPLEMENTATIONS)):
          return True
      # we are less sure about this but we can guess
      if line.startswith("py"):
          return True
      return False
docs: Given an input, checks whether the input is a request for python or notself.
  
      This can be a version, a python runtime name, or a generic 'python' or 'pythonX.Y'
  
      :param str line: A potential request to find python
      :returns: Whether the line is a python lookup
      :rtype: bool