Python date calculator

dates.py

'''Simple date calculator for an interview question, homework problem, or programming kata.

Renders any number of seconds as a breakdown by years, days, hours, minutes, and seconds,
with proper grammar and a friendly hello. Unit names and sizes are fully customizable.
'''

YEARS = {
    "singular": "year",
    "plural": "years",
    "next_unit": None
}
DAYS = {
    "singular": "day",
    "plural": "days",
    "next_unit": YEARS,
    "qty_in_next_unit": 365
}
MARTIAN_SOLS = {
    "singular": "sol",
    "plural": "sols",
    "next_unit": YEARS,
    "qty_in_next_unit": 670
}
HOURS = {
    "singular": "hour",
    "plural": "hours",
    # "next_unit": DAYS,
    # "qty_in_next_unit": 24
    # Uncomment below and comment above for Mars mode.
    "next_unit": MARTIAN_SOLS,
    "qty_in_next_unit": 25  # (note: rounded up. A real sol is about 24h/40m)
}
MINUTES = {
    "singular": "minute",
    "plural": "minutes",
    "next_unit": HOURS, 
    "qty_in_next_unit": 60
}
SECONDS = {
    "singular": "second",
    "plural": "seconds",
    "next_unit": MINUTES,
    "qty_in_next_unit": 60
}


def main():
    print('Welcome to the time calculator!')
    num_seconds = int(input('enter a number: '))
    formatted_time = format_segmented_time(calc_segmented_time(num_seconds))
    print(f"{num_seconds}s is " + formatted_time)
    print("Let me know if I can compute another time for you! I've got nothing but time.")


def format_segmented_time(segmented_time):
    rendered_segments = list(render_segments(segmented_time))
    if (len(rendered_segments) == 0):
      return 'no time at all!'
    elif (len(rendered_segments) == 1):
      return rendered_segments[0] + '.'
    elif (len(rendered_segments) == 2):
      return ' and '.join(rendered_segments) + '.'
    else:
      first_part = ', '.join(rendered_segments[0:-1])
      oxford_comma = f", and {rendered_segments[-1]}"
      return first_part + oxford_comma + '.'


def calc_segmented_time(qty, unit = SECONDS):
    next_unit = unit["next_unit"]
    if (qty == 0):
      return []
    elif next_unit is None:
      return [(qty, unit)]
    else:
      unit_size = unit["qty_in_next_unit"]
      out = qty % unit_size
      return calc_segmented_time(qty // unit_size, next_unit) + [(out, unit)]


def render_segments(segmented_time):
    for segment in segmented_time:
        rendered = render_time_segment(segment)
        if (rendered) != '':
            yield rendered


def render_time_segment(segment):
    (qty, unit) = segment
    if (qty == 0):
      return ""
    elif (qty == 1):
      return f"{qty} {unit['singular']}"
    else:
      return f"{qty} {unit['plural']}"


if __name__ == '__main__':
    main()