code: def get_contract_center(self, root_symbol, dt, offset):
          
          return self._get_active_contract_at_offset(root_symbol, dt, offset)
docs: Parameters
          ----------
          root_symbol : str
              The root symbol for the contract chain.
          dt : Timestamp
              The datetime for which to retrieve the current contract.
          offset : int
              The offset from the primary contract.
              0 is the primary, 1 is the secondary, etc.
  
          Returns
          -------
          Future
              The active future contract at the given dt.