嗨，我正在尝试将django-cities与django-location-field一起使用，以通过面向用户的谷歌地图输入来设置地理位置。我将以下字段添加到我的模型中以进行设置：
class Thing(models.Model):
city = models.ForeignKey(City)
location = LocationField(based_fields=[city], zoom=7, default=Point(1, 1), srid=3857)
objects = models.GeoManager()
之后我运行了架构迁移：
python2.7 manage.py schemamigration myapp --auto
? The field 'Thing.city' does not have a default specified, yet is NOT NULL.
? Since you are adding this field, you MUST specify a default
? value to use for existing rows. Would you like to:
? 1. Quit now, and add a default to the field in models.py
? 2. Specify a one-off value to use for existing columns now
? Please select a choice: 2
? Please enter Python code for your one-off default value.
? The datetime module is available, so you can do e.g. datetime.date.today()
>>> 0
+ Added field city on myapp.Thing
+ Added field location on myapp.Thing
Created 0002_auto__add_field_thing_city__add_field_thing_location.py. You can now apply this migration with: ./manage.py migrate myapp
但是在尝试迁移我的应用程序时，我收到了这个错误。但是，我不确定如何解决它：
[myproject]$ python2.7 manage.py migrate
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/myapp/lib/python2.7/django/core/management/__init__.py", line 443, in execute_from_command_line
utility.execute()
File "/myapp/lib/python2.7/django/core/management/__init__.py", line 382, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/myapp/lib/python2.7/django/core/management/base.py", line 196, in run_from_argv
self.execute(*args, **options.__dict__)
File "/myapp/lib/python2.7/django/core/management/base.py", line 232, in execute
output = self.handle(*args, **options)
File "/myapp/lib/python2.7/South-0.7.5-py2.7.egg/south/management/commands/migrate.py", line 107, in handle
ignore_ghosts = ignore_ghosts,
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/__init__.py", line 166, in migrate_app
Migrations.calculate_dependencies()
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 227, in calculate_dependencies
migration.calculate_dependencies()
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 358, in calculate_dependencies
for migration in self._get_dependency_objects("depends_on"):
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 338, in _get_dependency_objects
for app, name in getattr(self.migration_class(), attrname, []):
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 310, in migration_class
return self.migration().Migration
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/utils/__init__.py", line 62, in method
value = function(self)
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 301, in migration
raise exceptions.BrokenMigration(self, sys.exc_info())
south.exceptions.BrokenMigration: While loading migration 'myapp:0002_auto__add_field_thing_city__add_field_thing_location':
Traceback (most recent call last):
File "/lib/python2.7/South-0.7.5-py2.7.egg/south/migration/base.py", line 297, in migration
migration = __import__(full_name, {}, {}, ['Migration'])
File "/myapp/myproject/myapp/migrations/0002_auto__add_field_thing_city__add_field_thing_location.py", line 18
self.gf('location_field.models.LocationField')(default=<Point object at 0x277eeb0>, srid=3857),
^
SyntaxError: invalid syntax
如何修复此语法错误？谢谢你的想法！