def rename_datetimes(df):
    """Renaming tpep_pickup_datetime and tpep_dropoff_datetime into pickup_datetime, dropoff_datetime"""
    
    print("renaming datetimes")
    df = df.rename(columns={'tpep_pickup_datetime': 'pickup_datetime',
                            'tpep_dropoff_datetime': 'dropoff_datetime'})
    
    return df