gistfile1.txt

import pandas as pd

df = pd.read_excel('2016_Bike_Share_Toronto_Ridership_Q4.xlsx')

for col in ['trip_start_time', 'trip_stop_time']:
    df[col] = pd.to_datetime(df[col])
for col in ['trip_start_time', 'trip_stop_time']:
    swapped = pd.to_datetime({'year':df[col].dt.year, 
                              'month':df[col].dt.day, 
                              'day':df[col].dt.month,
                              'hour':df[col].dt.hour,
                              'minute':df[col].dt.minute,
                              'second':df[col].dt.second,}, errors='coerce')
    swapped = swapped.dropna()
    mask = swapped.index
    df.loc[mask, col] = swapped

# check that now all dates are in 2016Q4
for col in ['trip_start_time', 'trip_stop_time']:
    mask = (pd.PeriodIndex(df[col], freq='Q') == '2016Q4')
    assert mask.all()

# check that `trip_start_times` are in chronological order
assert (df['trip_start_time'].diff().dropna() >= pd.Timedelta(0)).all()

# check that `trip_stop_times` are always greater than `trip_start_times`
assert ((df['trip_stop_time']-df['trip_start_time']).dropna() >= pd.Timedelta(0)).all()