docs: Collection<MappingImpl> build(PropertyMap<S, D> propertyMap) {
      try {
        PROPERTY_MAP_CONFIGURE.invoke(propertyMap, this);
        saveLastMapping();
      } catch (IllegalAccessException e) {
        errors.errorAccessingConfigure(e);
      } catch (InvocationTargetException e) {
        Throwable cause = e.getCause();
        if (cause instanceof ConfigurationException)
          throw (ConfigurationException) cause;
        else
          errors.addMessage(cause, "Failed to configure mappings");
      } catch (NullPointerException e) {
        if (proxyErrors.hasErrors()) {
          throw proxyErrors.toException();
        }
        throw e;
      }
  
      errors.throwConfigurationExceptionIfErrorsExist();
      return propertyMappings;
    }