code: def check_and_make_label(lbl, lineno):
      
      if isinstance(lbl, float):
          if lbl == int(lbl):
              id_ = str(int(lbl))
          else:
              syntax_error(lineno, 'Line numbers must be integers.')
              return None
      else:
          id_ = lbl
  
      return global_.SYMBOL_TABLE.access_label(id_, lineno)
docs: Checks if the given label (or line number) is valid and, if so,
      returns a label object.
      :param lbl: Line number of label (string)
      :param lineno: Line number in the basic source code for error reporting
      :return: Label object or None if error.