res=sql_ask_database(conn,f"""SELECT chain_id from chain WHERE structure_id='{pdb_id}' AND chain_name='{pdb_chain_id}' AND rfam_acc IS NULL AND issue=0""")
res=sql_ask_database(conn,f"""SELECT chain_id from chain WHERE structure_id='{pdb_id}' AND chain_name='{pdb_chain_id}' AND rfam_acc = 'unmappd' AND issue=0""")
ifnotlen(res)orself.REUSE_ALL:# the chain is NOT yet in the database, or this is a known issue