public function getVariable(Ezer_AssignStepFromAttribute $from)
 {
     if (!isset($this->variables[$from->getVariable()])) {
         return null;
     }
     // TODO - check for from part
     return $this->variables[$from->getVariable()];
 }
 public function getVariableValue(Ezer_AssignStepFromAttribute $from)
 {
     if (!isset($this->variables[$from->getVariable()])) {
         return null;
     }
     return $this->getValueFromVariable($from, $this->variables[$from->getVariable()]);
 }