Вы можете иметь такую функцию:
def myfunc(Start_Date,End_Date):
Full_Year_Goal = None
if (Start_Date == '2014-07-27' or Start_Date == '2014-07-27') and End_Date == '2015-07-25':
Full_Year_Goal = 'Y'
elif (Start_Date == '2015-07-26' or Start_Date == '2015-07-27') and End_Date == '2016-07-30':
Full_Year_Goal = 'Y'
elif (Start_Date == '2016-07-31' and End_Date == '2017-07-29'):
Full_Year_Goal = 'Y'
elif (Start_Date == '2017-07-30' or Start_Date == '2017-07-31') and End_Date == '2018-07-28':
Full_Year_Goal = 'Y'
else:
Full_Year_Goal = 'N'
return Full_Year_Goal
Затем вызывать ее как:
Full_Year_Goal = my_func('2014-06-27', '2014-08-25')