<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def parse(self):
 """ Convert ACIS 'll' value into separate latitude and longitude. """

        super(AcisIO, self).parse()

        # This is more of a "mapping" step than a "parsing" step, but mappers
        # only allow one-to-one mapping from input fields to output fields.
        for row in self.data:
            if 'meta' in row:
                row = row['meta']
            if 'll' in row:
                row['longitude'], row['latitude'] = row['ll']
                del row['ll']