code: public static Set<String> findPrefixesForImportedVariables( Instance instance ) {
  		Set<String> result = new HashSet<> ();
  
  		for( ImportedVariable var : ComponentHelpers.findAllImportedVariables( instance.getComponent()).values())
  			result.add( VariableHelpers.parseVariableName( var.getName()).getKey());
  
  		return result;
  	}
docs: Finds the component and facet names that prefix the variables an instance imports.
  @param instance an instance
  @return a non-null set with all the component and facet names this instance imports