'Returns true if there is reference data for the specified dbkey. If dbkey is custom,
dbkey_owner is needed to determine if there is reference data.'

def has_reference_data(self, dbkey, dbkey_owner=None):

    self.check_and_reload()
    if ((dbkey in self.genomes) and self.genomes[dbkey].twobit_file):
        return True
    if (dbkey_owner and ('dbkeys' in dbkey_owner.preferences)):
        user_keys = loads(dbkey_owner.preferences['dbkeys'])
        if (dbkey in user_keys):
            dbkey_attributes = user_keys[dbkey]
            if ('fasta' in dbkey_attributes):
                return True
    return False
