code: def _execute_insert(self, conn, keys, data_iter):
          
          data = [dict(zip(keys, row)) for row in data_iter]
          conn.execute(self.table.insert(), data)
docs: Execute SQL statement inserting data
  
          Parameters
          ----------
          conn : sqlalchemy.engine.Engine or sqlalchemy.engine.Connection
          keys : list of str
             Column names
          data_iter : generator of list
             Each item contains a list of values to be inserted