code: public static EquivalentFragmentSet plays(VarProperty varProperty, Variable type, Variable role, boolean required) {
          return new AutoValue_PlaysFragmentSet(varProperty, type, role, required);
      }
docs: An {@link EquivalentFragmentSet} that indicates a variable is a type whose instances play a role.
  
  @param type a type variable label
  @param role a role variable label
  @param required whether the plays must be constrained to be "required"