input: Write a python function to convert a SAP timestamp to a datetime object.
  assert saptimestamp_to_datetime(1325376000) == datetime(2012, 1, 1, 0, 0)
  assert saptimestamp_to_datetime(1356998400) == datetime(2013, 1, 1, 0, 0)
  assert saptimestamp_to_datetime(1388534400) == datetime(2014, 1, 1, 0, 0)
output: from datetime import datetime
  
  def saptimestamp_to_datetime(sap_timestamp):
      return datetime.utcfromtimestamp(sap_timestamp)