code: public Project createSubProject(String name, DateTime beginDate, Schedule schedule) {
          return getInstance().create().project(name, this, beginDate, schedule);
      }
docs: Create a sub project under this project with a name, begin date, and
  optional schedule.
  
  @param name      Name of the new project.
  @param beginDate Date the schedule will begin.
  @param schedule  The new schedule. If null, the project will inherit the
  parent project's schedule.
  @return The newly created project.