code: def drop_account(self, account_cookie):
          
  
          if account_cookie in self.account_list:
              res = self.account_list.remove(account_cookie)
              self.cash.append(
                  self.cash[-1] + self.get_account_by_cookie(res).init_cash)
              return True
          else:
              raise RuntimeError(
                  'account {} is not in the portfolio'.format(account_cookie)
              )
docs: 删除一个account
  
          Arguments:
              account_cookie {[type]} -- [description]
  
          Raises:
              RuntimeError -- [description]