code: def calculate_time_difference(startDate, endDate):
      
      ################ > IMPORTS ################
      from datetime import datetime
      from dateutil import relativedelta
  
      ################ > VARIABLE SETTINGS ######
  
      ################ >ACTION(S) ################
      if "T" not in startDate:
          startDate = startDate.strip().replace(" ", "T")
      if "T" not in endDate:
          endDate = endDate.strip().replace(" ", "T")
      startDate = datetime.strptime(startDate, '%Y-%m-%dT%H:%M:%S')
      endDate = datetime.strptime(endDate, '%Y-%m-%dT%H:%M:%S')
      d = relativedelta.relativedelta(endDate, startDate)
  
      relTime = ""
      if d.years > 0:
          relTime += str(d.years) + "yrs "
      if d.months > 0:
          relTime += str(d.months) + "mths "
      if d.days > 0:
          relTime += str(d.days) + "dys "
      if d.hours > 0:
          relTime += str(d.hours) + "h "
      if d.minutes > 0:
          relTime += str(d.minutes) + "m "
      if d.seconds > 0:
          relTime += str(d.seconds) + "s"
      ###############################
  
      if relTime == "":
          relTime = "0s"
  
      return relTime
docs: *Return the time difference between two dates as a string*
  
      **Key Arguments:**
          - ``startDate`` -- the first date in YYYY-MM-DDTHH:MM:SS format
          - ``endDate`` -- the final date YYYY-MM-DDTHH:MM:SS format
  
      **Return:**
          - ``relTime`` -- the difference between the two dates in Y,M,D,h,m,s (string)
  
      **Usage:**
          .. code-block:: python 
  
              from fundamentals import times
              diff = times.calculate_time_difference(startDate="2015-10-13 10:02:12", endDate="2017-11-04 16:47:05")
              print diff
  
              # OUT: 2yrs 22dys 6h 44m 53s