code: public TraceStep getLastStep() {
  		TraceStep result = this;
  		while (true) {
  			if (result.children == null || result.children.size() == 0)
  				return result;
  			result = result.children.get(result.children.size() - 1);
  		}
  	}
docs: Returns the last step in this execution.
  
  @return this step if it has no chidlren or the last step from the children.