function extractTaprootSigs(input) {
  const sigs = [];
  if (input.tapKeySig) sigs.push(input.tapKeySig);
  if (input.tapScriptSig)
    sigs.push(...input.tapScriptSig.map(s => s.signature));
  if (!sigs.length) {
    const finalTapKeySig = getTapKeySigFromWitness(input.finalScriptWitness);
    if (finalTapKeySig) sigs.push(finalTapKeySig);
  }
  return sigs;
}
Extracts taproot signatures from a PSBT input.
@param input The PSBT input to extract signatures from.
@returns An array of taproot signatures.