'Dump custom field mappings for debugging'

def dump_custom_fields(self):

    if self.opts.verbose:
        self.opts.log.info('    Custom    fields:')
        all_custom_fields = self.db.custom_field_keys()
        for cf in all_custom_fields:
            self.opts.log.info(('        %-20s    %-20s    %s' % (cf, ("'%s'" % self.db.metadata_for_field(cf)['name']), self.db.metadata_for_field(cf)['datatype'])))
