code: public void setGoal(com.google.api.ads.admanager.axis.v201811.Goal goal) {
          this.goal = goal;
      }
docs: Sets the goal value for this ProposalLineItem.
  
  @param goal   * The goal(i.e. contracted quantity, quantity or limit) that
  this {@code ProposalLineItem} is
  associated with, which is used in its pacing and budgeting.
  {@link Goal#units} must be greater
  than 0 when the proposal line item turns into a line
  item, {@link Goal#goalType} and {@link
  Goal#unitType} are readonly.
  For a Preferred deal {@code ProposalLineItem}, the
  goal type can only be {@link GoalType#NONE}.
  <span class="constraint Required">This attribute is
  required.</span>