Validates a style and associated value.

    Arguments
    ---------
    style: str
       The style to validate (e.g. 'color', 'size' or 'marker')
    value:
       The style value to validate
    vectorized: bool
       Whether validator should allow vectorized setting

    Returns
    -------
    valid: boolean or None
       If validation is supported returns boolean, otherwise None

def validate(style, value, vectorized=True):
    """
    Validates a style and associated value.

    Arguments
    ---------
    style: str
       The style to validate (e.g. 'color', 'size' or 'marker')
    value:
       The style value to validate
    vectorized: bool
       Whether validator should allow vectorized setting

    Returns
    -------
    valid: boolean or None
       If validation is supported returns boolean, otherwise None
    """
    validator = get_validator(style)
    if validator is None:
        return None
    if isinstance(value, (np.ndarray, list)) and vectorized:
        return all(validator(v) for v in value)
    try:
        valid = validator(value)
        return False if valid == False else True
    except:
        return False