def from_flags(flags, ednsflags):
    """Return the rcode value encoded by flags and ednsflags.

    @param flags: the DNS flags
    @type flags: int
    @param ednsflags: the EDNS flags
    @type ednsflags: int
    @raises ValueError: rcode is < 0 or > 4095
    @rtype: int
    """

    value = (flags & 0x000f) | ((ednsflags >> 20) & 0xff0)
    if value < 0 or value > 4095:
        raise ValueError('rcode must be >= 0 and <= 4095')
    return value
Return the rcode value encoded by flags and ednsflags.

    @param flags: the DNS flags
    @type flags: int
    @param ednsflags: the EDNS flags
    @type ednsflags: int
    @raises ValueError: rcode is < 0 or > 4095
    @rtype: int