<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_meta_line(self, key, value):
 """ Adds an arbitrary metadata line to the header. This must be a key value pair Arguments: key (str):
 The key of the metadata line value (str):
 The value of the metadata line """

        meta_line = '##{0}={1}'.format(
            key, value
        )
        logger.info("Adding meta line to vcf: {0}".format(meta_line))
        self.parse_meta_data(meta_line)
        return