calculate_age_in_minutes explained

age_in_minutes.py

def calculate_age_in_minutes(rec_time, pub_time):
  """
  pub_time .. string with datetime in ISO 8601 format. Time, when is the feed published (mostly current time).
  rec_time .. string with datetime in ISO 8601 format. Time, when record was created.
  
    sample ISO string: 2011-10-25T13:55:42.123Z
  return .. integer with duration between pub_time and rec_time expressed in minutes
  """
  #parsing pub_time to datetime structure. Ignoring timezone and fractions of seconds
  pub_t = datetime.datetime.strptime(pub_time[:19],"%Y-%m-%dT%H:%M:%S")
  #parsing rec_time to datetime structure. Ignoring timezone and fractions of seconds
  rec_t = datetime.datetime.strptime(rec_time[:19],"%Y-%m-%dT%H:%M:%S")
  #calculating duration between publication time and record time (as time delta structure)
  td = pub_t - rec_t
  #convert duration td to minutes.
  return int(((td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6) / 60)
  #above calculation can be probably simplified - skip microseconds and get rid of multiply/divide by 10**6