User_ModelView_error

Traceback (most recent call last):
  File "run.py", line 3, in <module>
    from pos import app
  File "/home/zaphod/Documents/flask/pos/pos/__init__.py", line 17, in <module>
    from pos import views, models
  File "/home/zaphod/Documents/flask/pos/pos/views.py", line 67, in <module>
    admin.add_view(ModelView(User, db.session))
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/contrib/sqla/view.py", line 271, in __init__
    super(ModelView, self).__init__(model, name, category, endpoint, url)
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/model/base.py", line 495, in __init__
    self._refresh_cache()
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/model/base.py", line 503, in _refresh_cache
    self._list_columns = self.get_list_columns()
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/model/base.py", line 614, in get_list_columns
    columns = self.scaffold_list_columns()
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/contrib/sqla/view.py", line 339, in scaffold_list_columns
    if column.foreign_keys and not is_inherited_primary_key(p):
  File "/home/zaphod/Documents/myProject/venv/local/lib/python2.7/site-packages/flask_admin/contrib/sqla/tools.py", line 54, in is_inherited_primary_key
    if prop.expression.primary_key:
AttributeError: 'ColumnProperty' object has no attribute 'expression'