DateType is a date-identifier. At base, it is a floating-point number expressing seconds since the epoch (nominally 1-Jan-1970 0:00 UTC).
In Python, properties of this value will be returned as PyTime objects. It can be converted to a timestamp using float() or int():
lpDate = track.DatePlayed timestamp = float(lpDate) # or int(lpDate) dateobj = datetime.utcfromtimestamp(timestamp)