def ishexadecimal(value):
    """
    Return whether or not given value is a hexadecimal number.
    If the value is a hexadecimal number, this function returns ``True``, otherwise ``False``.

    Examples::

        >>> ishexadecimal('deadBEEF')
        True

        >>> ishexadecimal('abcdefg')
        False

    :param value: string to validate hexadecimal number
    """
    try:
        return int(value, 16) >= 0
    except ValueError:
        return False