code: public static Ref createHeadRef(int headOffset) {
      CheckUtilities.checkIntArgumentGreaterThan(headOffset, -1, "headOffset");
  
      if (0 == headOffset) {
        return HEAD;
      } else if (1 == headOffset) {
        return HEAD_1;
      }
  
      Ref cn = new Ref();
      cn.refType = RefType.HEAD;
      cn.headOffset = headOffset;
      return cn;
    }
docs: Creates a <code>Ref</code> of type <code>HEAD</code>.
  
  @param headOffset
  The offset of the commit back from the HEAD commit on the current working branch. If
  the value is less than zero, an <code>IllegalArgumentException</code> is thrown.
  @return A <code>Ref</code> instance of type <code>HEAD</code>.