code: public List<ProjectRoleSpreadType.Period> getPeriod()
     {
        if (period == null)
        {
           period = new ArrayList<ProjectRoleSpreadType.Period>();
        }
        return this.period;
     }
docs: Gets the value of the period property.
  
  <p>
  This accessor method returns a reference to the live list,
  not a snapshot. Therefore any modification you make to the
  returned list will be present inside the JAXB object.
  This is why there is not a <CODE>set</CODE> method for the period property.
  
  <p>
  For example, to add a new item, do as follows:
  <pre>
  getPeriod().add(newItem);
  </pre>
  
  
  <p>
  Objects of the following type(s) are allowed in the list
  {@link ProjectRoleSpreadType.Period }