code: private BioPAXElement getIdentical(BioPAXElement bpe)
  	{
  		int key = bpe.hashCode();
  		List<BioPAXElement> list = equivalenceMap.get(key);
  		if (list != null)
  		{
  			for (BioPAXElement other : list)
  			{
  				if (other.equals(bpe))
  				{
  					return other;
  				}
  			}
  		}
  		return null;
  	}
docs: Searches the target model for an identical of given BioPAX element, and returns this element if
  it finds it.
  
  @param bpe BioPAX element for which equivalent will be searched in target.
  @return the BioPAX element that is found in target model, if there is none it returns null