Sometimes you just need to create a timestamp in Python with no dependencies. This function creates timestamps without requiring any imports.

pp_timestamp.py

def pure_python_timestamp(year, month, day, hour, minute, seconds):
    """
    Sometimes you just need to create a timestamp in Python with no dependencies. 
    This function creates timestamps without requiring any imports.

    Note: This function doesn't fully take into account the century rules for leap years.

    >>> pure_python_timestamp('1994','11','19', '22', '01', '22')
    785282482
    >>> pure_python_timestamp('2013','07','03', '08', '14', '15')
    1372839255
    >>> pure_python_timestamp('2020','02','29', '06', '18', '37')
    1582957117
    >>> pure_python_timestamp('2020','05','21', '07', '02', '01')
    1590044521
    >>> pure_python_timestamp('2031','12','17', '23', '56', '47')
    1955318207

    """
    days_before_month = {
        '01': 0, '02': 31, '03': 59, '04': 90, '05': 120, '06': 151,
        '07': 181, '08': 212, '09': 243, '10': 273, '11': 304, '12': 334,
    }

    epoch_start = 1970
    leap_year_after_epoch = 1972

    # We're going to be using this a lot, so going to cast it early
    year = int(year)

    # Create the base timestamp with regular math
    years_since_epoch = year - epoch_start
    timestamp = (years_since_epoch * 31536000) \
                + (days_before_month[month] * 86400) \
                + (int(day) * 86400) \
                + (int(hour) * 3600) \
                + (int(minute) * 60) \
                + int(seconds)

    # Some crazy logic to figure out if it's a leap year
    if year % 400 == 0:
        leap_year = True
    elif year % 100 == 0:
        leap_year = False
    elif year % 4 == 0:
        leap_year = True
    else:
        leap_year = False

    # Some logic to account for the extra days from past leap years
    if leap_year is False:
        past_leap_years = ((year - leap_year_after_epoch) / 4) * 86400
    else:
        if int(month) < 3:
            past_leap_years = ((year - leap_year_after_epoch) / 4) * 86400
            past_leap_years = past_leap_years - 86400
        else:
            past_leap_years = ((year - leap_year_after_epoch) / 4) * 86400

    # Add the days from past leap years to the timestamp
    timestamp = timestamp + past_leap_years

    return timestamp

if __name__ == "__main__":
    import doctest
    doctest.testmod()