code: public org.grails.datastore.mapping.query.api.Criteria eq(String propertyName, Object propertyValue) {
          return eq(propertyName, propertyValue, Collections.emptyMap());
      }
docs: Creates an "equals" Criterion based on the specified property name and value. Case-sensitive.
  @param propertyName The property name
  @param propertyValue The property value
  
  @return A Criterion instance