code: def find_python(finder, line=None):
      
  
      if line and not isinstance(line, six.string_types):
          raise TypeError(
              "Invalid python search type: expected string, received {0!r}".format(line)
          )
      if line and os.path.isabs(line):
          if os.name == "nt":
              line = posixpath.join(*line.split(os.path.sep))
          return line
      if not finder:
          from pipenv.vendor.pythonfinder import Finder
          finder = Finder(global_search=True)
      if not line:
          result = next(iter(finder.find_all_python_versions()), None)
      elif line and line[0].isdigit() or re.match(r'[\d\.]+', line):
          result = finder.find_python_version(line)
      else:
          result = finder.find_python_version(name=line)
      if not result:
          result = finder.which(line)
      if not result and not line.startswith("python"):
          line = "python{0}".format(line)
          result = find_python(finder, line)
      if not result:
          result = next(iter(finder.find_all_python_versions()), None)
      if result:
          if not isinstance(result, six.string_types):
              return result.path.as_posix()
          return result
      return
docs: Given a `pythonfinder.Finder` instance and an optional line, find a corresponding python
  
      :param finder: A :class:`pythonfinder.Finder` instance to use for searching
      :type finder: :class:pythonfinder.Finder`
      :param str line: A version, path, name, or nothing, defaults to None
      :return: A path to python
      :rtype: str