code: def python_version_matchers():
      
      version = sys.version_info
      patterns = [
          "{0}",
          "{0}{1}",
          "{0}.{1}",
      ]
      matchers = [
          pattern.format(*version)
          for pattern in patterns
      ] + [None]
      return set(matchers)
docs: Return set of string representations of current python version