persistence/play-java-jpa/src/main/java/play/db/jpa/DefaultJPAApi.java
public <T> T withTransaction(String name, Function<EntityManager, T> block) {
    return withTransaction(name, false, block);
  }
public <T> T withTransaction(String name, Function<EntityManager, T> block) {
    return withTransaction(name, false, block);
  }
Run a block of code with a newly created EntityManager for the named Persistence Unit.

@param name The persistence unit name
@param block Block of code to execute
@param <T> type of result
@return code execution result