Currently, the multisig descriptor constructions are limited to 16 keys only possibly because of template parsing reasons. Under p2sh context, such scripts would be invalid anyway because of 520-byte rule, but we can support up to 20 keys for CHECKMULTISIG in witness script context. 


assert(0 <= opcode && opcode <= OP_PUSHDATA4);
    if (data.size() == 0) {
        
        return opcode == OP_0;
    } else if (data.size() == 1 && data[0] >= 1 && data[0] <= 16) {
        
        return false;
    } else if (data.size() == 1 && data[0] == 0x81) {
        
        return false;
    } else if (data.size() <= 75) {
        
        return opcode == data.size();
    } else if (data.size() <= 255) {
        
        return opcode == OP_PUSHDATA1;
    } else if (data.size() <= 65535) {
        
        return opcode == OP_PUSHDATA2;
    }
    return true;
}
int FindAndDelete(CScript& script, const CScript& b)