code: public Period setStart( Date theDate,  TemporalPrecisionEnum thePrecision) {
      start = new DateTimeType(theDate, thePrecision); 
      return this; 
    }
docs: Sets the value for <b>start</b> ()
  
  <p>
  <b>Definition:</b>
  The start of the period. The boundary is inclusive.
  </p>