code: def param_spec(line: str) -> str | None:
      """
      Identify and return parameter
  
      Parameters
      ----------
      line : str
          A line in the parameter section.
  
      Returns
      -------
      name : str | None
          Name of the parameter if the line for the parameter
          type specification and None otherwise.
  
      Examples
      --------
      >>> param_spec('line : str')
      breaks
      >>> param_spec("    A line in the parameter section.")
      """
      m = PARAM_PATTERN.match(line)
      return m.group(1) if m else None
  
file_path: plotnine/plotnine/doctools.py
imports: from __future__ import annotations
  import itertools
  import os
  import re
  import typing
  from functools import lru_cache
  from textwrap import dedent, indent
label_desc: Use image node_id 6 for calling a global function with example usage: param_spec(line) and returns: unknown