code: public boolean hasReferenceTo(EntitySpec entitySpec) {
          if (entitySpec == null) {
              throw new IllegalArgumentException("entitySpec cannot be null");
          }
  
          boolean found = false;
          String entitySpecName = entitySpec.name;
          for (ReferenceSpec refSpec : this.referenceSpecs) {
              if (refSpec.getEntityName().equals(entitySpecName)) {
                  found = true;
                  continue;
              }
          }
          return found;
      }
docs: Returns whether this entity spec has a reference to another entity spec.
  
  @param entitySpec another entity spec.
  @return <code>true</code> or <code>false</code>.