def number_of_nonisomorphic_trees(order):
 return sum((1 for _ in nonisomorphic_trees(order)))

def number_of_nonisomorphic_trees ( order ) : return sum ( ( 1 for _ in nonisomorphic_trees ( order ) ) )
returns the number of nonisomorphic trees parameters order : int order of the desired tree(s) returns length : number of nonisomorphic graphs for the given order references .