code: def _check_for_indent(self, newline_token):
          
          indent_delta = self._get_next_line_indent_delta(newline_token)
          if indent_delta is None or indent_delta == 1:
              # Next line's indent isn't relevant (e.g. it's a comment) OR
              # next line is correctly indented.
              return None
          else:
              self.errors.append(
                  ('Line continuation must increment indent by 1.',
                   newline_token.lexer.lineno))
docs: Checks that the line following a newline is indented, otherwise a
          parsing error is generated.