For preserving indents
        :param line:
        :return:

def leading_whitespace(self, line):  # type: (str) -> str
        """
        For preserving indents
        :param line:
        :return:
        """
        string = ""
        for char in line:
            if char in " \t":
                string += char
                continue
            else:
                return string
        return string