def _timestep_cull(self, timestep):
new_values = []<EOL>new_datetimes = []<EOL>mins_per_step = int(<NUM_LIT> / timestep)<EOL>for i, date_t in enumerate(self.datetimes):<EOL><INDENT>if date_t.moy % mins_per_step == <NUM_LIT:0>:<EOL><INDENT>new_datetimes.append(date_t)<EOL>new_values.append(self.values[i])<EOL><DEDENT><DEDENT>a_per = self.header.analysis_period<EOL>new_ap = AnalysisPeriod(a_per.st_month, a_per.st_day, a_per.st_hour,<EOL>a_per.end_month, a_per.end_day, a_per.end_hour,<EOL>timestep, a_per.is_leap_year)<EOL>return new_ap, new_values, new_datetimes<EOL>
Cull out values that do not fit a timestep.