Calculate the length of a password for a given entropy and chars.

def password_length_needed(entropybits: Union[int, float], chars: str) -> int:
    """Calculate the length of a password for a given entropy and chars."""
    if not isinstance(entropybits, (int, float)):
        raise TypeError('entropybits can only be int or float')
    if entropybits < 0:
        raise ValueError('entropybits should be greater than 0')
    if not isinstance(chars, str):
        raise TypeError('chars can only be string')
    if not chars:
        raise ValueError("chars can't be null")

    # entropy_bits(list(characters)) = 6.554588
    entropy_c = entropy_bits(list(chars))
    return ceil(entropybits / entropy_c)