code: def decode_signature(sigb64):
      
      sig_bin = base64.b64decode(sigb64)
      if len(sig_bin) != 64:
          raise ValueError("Invalid base64 signature")
  
      sig_hex = sig_bin.encode('hex')
      sig_r = int(sig_hex[:64], 16)
      sig_s = int(sig_hex[64:], 16)
      return sig_r, sig_s
docs: Decode a signature into r, s