ImportError：Django Cities

Question

我想知道为什么我在使用django-cities时获得ImportError。

from cities.models import PostalCode

我已经同步了数据库中存在的db和cities表。追溯：

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
   File "/lib/python2.7/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/lib/python2.7/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/lib/python2.7/django/core/management/__init__.py", line 261, in fetch_command
    klass = load_command_class(app_name, subcommand)
  File "/lib/python2.7/django/core/management/__init__.py", line 69, in load_command_class
    module = import_module('%s.management.commands.%s' % (app_name, name))
  File "/lib/python2.7/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/lib/python2.7/South-0.7.5-py2.7.egg/south/management/commands/__init__.py", line 10, in <module>
    import django.template.loaders.app_directories
  File "/lib/python2.7/django/template/loaders/app_directories.py", line 23, in <module>
    raise ImproperlyConfigured('ImportError %s: %s' % (app, e.args[0]))
django.core.exceptions.ImproperlyConfigured: ImportError haystack: cannot import name PostalCode

ImportError建议python在PostalCode中寻找haystack，但我要求它从cities导入..为什么会发生这种情况？谢谢你的想法！

Answer 1

我弄明白了这个问题。尽管github和pypi版本都声称为0.2，但事实证明它们是不同的。我通过pip安装，而pypi版本没有PostalCode模型类，这是我的ImportError的来源。谢谢！

Answer 2

问题更可能发生在你的models.py某个地方。您可以进行循环导入（换句话说，A从B导入，B从B导入）。