code: def version(path):
      
      version_file = read(path)
      version_match = re.search(r"""^__version__ = ['"]([^'"]*)['"]""",
                                version_file, re.M)
      if version_match:
          return version_match.group(1)
      raise RuntimeError("Unable to find version string.")
docs: Obtain the packge version from a python file e.g. pkg/__init__.py
      See <https://packaging.python.org/en/latest/single_source_version.html>.