# time units and their values in multiples of seconds
time_units= {
    11574: 1.0, # second
    7727: 60.0, # minute
    25235: 3600.0, # hour
    573: 86400.0, # day
    23387: 604800.0, # week
    5151: 2.630e6, # month (average)
    1092296: 3.156e7, # year (annum)
    577: 3.156e7, # year (calendar)
    723733: 1.0e-3, # millisecond
    842015: 1.0e-6, # microsecond
    838801: 1.0e-9, # nanosecond
    3902709: 1.0e-12, # picosecond
    1777507: 1.0e-15, # femtosecond
    2483628: 1.0e-18 # attosecond
}

def time_quantity_in_seconds(claim):
    amount = None
    if 'mainsnak' in claim:
      if 'datavalue' in claim['mainsnak']:
        quantity = claim['mainsnak']['datavalue']['value']
        amount = float(quantity['amount'])
        unit_uri = quantity['unit'] # Has form http://www.wikidata.org/entity/Q577
        unit_id = int(unit_uri.split('/')[-1].replace('Q',''))
	amount *= time_units[unit_id]
    return amount