function to concatenate the 2 nd ( back ) list at the end of the 1 st ( front ) list and returns the head of the new list
def concatFrontAndBackList ( front , back ) : NEW_LINE INDENT head = front NEW_LINE if ( front == None ) : NEW_LINE INDENT return back NEW_LINE DEDENT while ( front . next != None ) : NEW_LINE INDENT front = front . next NEW_LINE DEDENT front . next = back NEW_LINE return head NEW_LINE DEDENT