def has_unique_solution(puzzle: Puzzle, clues: Iterable[Clue]) -> bool:
"""Test if a puzzle has a unique solution under a given set of clues."""
with puzzle.with_clues(clues):
print(f"Testing puzzle with {len(puzzle.clues)} clues")
solutions = itersolve(puzzle.as_cnf())
_first_solution = next(solutions)
# test if second solution exists or not; if it doesn't, uniquely solvable
if next(solutions, None) is None:
return True
else:
return False
