code: public function getBlock($blockName)
      {
          if (!array_key_exists($blockName, $this->blocks)) {
              throw new Exception('Unable to find block with name ' . $blockName);
          }
  
          return $this->blocks[$blockName];
      }
docs: Returns block information associated to specified block name
  
  @param $blockName
  @return Sheep_Debug_Model_Block
  @throws Exception