Durations are serialized to conform with ISO 8601 and are represented by the following format:
P[n]Y[n]M[n]DT[n]H[n]M[n]S
- P: This is the duration designator (historically called "period") placed at the start of the duration representation
- Y: This is the year designator that follows the value for the number of years
- M: This is the month designator that follows the value for the number of months
- W: This is the week designator that follows the value for the number of weeks
- D: This is the day designator that follows the value for the number of days
- T: This is the time designator that precedes the time components of the representation
- H: This is the hour designator that follows the value for the number of hours
- M: This is the minute ...