@staticmethod<EOL><INDENT>def diff_in_years(start, end):<DEDENT>
return BaseDateDatetimeDate.diff_in_days(start, end) / DAYS_IN_YEAR<EOL>
calculate difference between given dates in years. The difference corresponds to Act/365.25 year fraction

:param BaseDateDatetimeDate start: state date
:param BaseDateDatetimeDate end: end date
:return float: difference between end date and start date in years