in src/main/scala/com.gu.conf/impl/AbstractConfiguration.scala [29:39]
def getPropertySource(propertyName: String): Option[AbstractConfiguration]
/**
* Return a projection of this configuration to the given set of properties
*
* @param properties the names of the properties to retain in the projection
* @return this configuration with only the named properties
*/
def project(properties: Set[String]): AbstractConfiguration = {
new ProjectedConfiguration(this, properties)
}