unit testing - dynamic value for the data provider in python -

i using lambda data provider unit test in python. if send static variable means can result. if use dynamic variable means have encountered problem. , coding

class testone(unittest.testcase):      data=lambda: (             ((tc.read_data_from_excel('inputdata.xls','data','datalevel1')),),         )       def setup(self):         self.driver =webdriver.firefox()         self.driver.maximize_window()      @data_provider(data)     def test(self,username,password):                 //coding here 

here excel file having username , password , write method 'read_data_from_excel' retrieve data , return list. did wrong