Python style: if versus exceptions

What is the recommended structure to write validate functions with many conditions? See these two examples. The first looks ugly, the second isn't very common, perhaps because assert is generally used to rule out unexpected behaviour. Are there better alternatives?

def validate(val):
  if cond1(val):
    return False
  if cond2(val):
    return False
  if cond3(val)
    return False
  return True

Or

def validate(val):
  try:
    assert cond1(val)
    assert cond2(val)
    assert cond3(val)
    return True
  except AssertionError:
    return False