public Configuration configuration(String identity, String variant) {
    Config config = configurations.get(identity);
    if (config == null) {
      return null;
    } else {
      return config.configuration(variant);
    }
  }
public Configuration configuration ( String identity , String variant ) { Config config = configurations . get ( identity ) ; if ( config == null ) { return null ; } else { return config . configuration ( variant ) ; } }
Retrieve the singular configuration for {@code identity} and {@code variant}.
<p>
If the given identity is associated only with a singular configuration then that configuration will be returned for
all variants.

@param identity identity to retrieve
@param variant variant to retrieve
@return the configuration for the given identity; {@code null} if the identity is not in this configuration
@throws IllegalArgumentException if the given variant does not exist