pykeepass python 代码：'NoneType' 对象没有属性 'payload'

如何解决pykeepass python 代码：'NoneType' 对象没有属性 'payload'

from pykeepass import PyKeePass

try:
        kp = PyKeePass("newdb.kdb",password="qwerty@123")
except:
        print("Got exception")

lstEntry = kp.find_entries_by_notes(".*testing.*",regex=True)

print(lstEntry)

以下是错误

Traceback (most recent call last):
  File "keeps.py",line 8,in <module>
    lstEntry = kp.find_entries_by_notes(".*testing.*",regex=True)
  File "/home/oracle/env/lib64/python3.6/site-packages/pykeepass/pykeepass.py",line 564,in find_entries_by_notes
    first=first
  File "/home/oracle/env/lib64/python3.6/site-packages/pykeepass/pykeepass.py",line 508,in find_entries
    res = self._find(prefix,entry_xp,path=path,tree=group,**kwargs)
  File "/home/oracle/env/lib64/python3.6/site-packages/pykeepass/pykeepass.py",line 362,in _find
    **kwargs
  File "/home/oracle/env/lib64/python3.6/site-packages/pykeepass/pykeepass.py",line 279,in _xpath
    tree = self.tree
  File "/home/oracle/env/lib64/python3.6/site-packages/pykeepass/pykeepass.py",line 200,in tree
    return self.kdbx.body.payload.xml
AttributeError: 'nonetype' object has no attribute 'payload'