parameters: (self, p)
docstring: OptionalType : ',' Type
                      |
docstring_summary: OptionalType : ',' Type
                      |
docstring_tokens: OptionalType : Type |
function: def p_OptionalType(self, p):
      """OptionalType : ',' Type
                      |"""
      if len(p) > 1:
        p[0] = p[2]
function_tokens: def p_OptionalType ( self , p ) : if len ( p ) > 1 : p [ 0 ] = p [ 2 ]