Python 3.6 Import BER into chilkat.CkAsn()

Dear, I do not manage to importer a "bytes" variable into a chilkat.CkAsn() structure. I check with

• asn = chilkat.CkAsn()
• bytedata = chilkat.CkByteData()
• bytedata.append2(payload,len(payload))
• success = asn.LoadBinary(bytedata)

But but without success, i receive this error

• return _chilkat.CkByteData_append2(self, data, numBytes)
  
• TypeError: in method 'CkByteData_append2', argument 2 of type 'char const *'"

Can you help me, Thanx in advance, Jacky