code: def database_create(self, database, **params):
          
          binds = {}
          dbname = database
          for key, engine in self.keys_engines():
              if hasattr(database, '__call__'):
                  dbname = database(engine)
              assert dbname, "Cannot create a database, no db name given"
              key = key if key else 'default'
              binds[key] = self._database_create(engine, dbname)
          return self.copy(binds)
docs: Create databases for each engine and return a new :class:`.Mapper`.