code: def init_db(drop_all=False, bind=engine):
      
      try:
          if drop_all:
              Base.metadata.drop_all(bind=bind)
          Base.metadata.create_all(bind=bind)
      except OperationalError as err:
          msg = 'password authentication failed for user "dallinger"'
          if msg in err.message:
              sys.stderr.write(db_user_warning)
          raise
  
      return session
docs: Initialize the database, optionally dropping existing tables.