code: def effective_balance(self, address: Address, block_identifier: BlockSpecification) -> Balance:
          
          fn = getattr(self.proxy.contract.functions, 'effectiveBalance')
          balance = fn(address).call(block_identifier=block_identifier)
  
          if balance == b'':
              raise RuntimeError(f"Call to 'effectiveBalance' returned nothing")
  
          return balance
docs: The user's balance with planned withdrawals deducted.