parameters: (self, key)
return_statement: return key.upper()
docstring: Normalize a header name for use as a key.
docstring_summary: Normalize a header name for use as a key.
docstring_tokens: Normalize a header name for use as a key .
function: def _normalize_key(self, key):
      """Normalize a header name for use as a key."""
      return key.upper()
function_tokens: def _normalize_key ( self , key ) : return key . upper ( )