Alembic 0.5.0 Postgres Partial Index stack trace

gistfile1.txt

Traceback (most recent call last):
  File "/Users/sth/dev/brockley_analytics/venv/bin/alembic", line 8, in <module>
    load_entry_point('alembic==0.5.0', 'console_scripts', 'alembic')()
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/config.py", line 265, in main
    CommandLine(prog=prog).main(argv=argv)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/config.py", line 260, in main
    self.run_cmd(cfg, options)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/config.py", line 247, in run_cmd
    **dict((k, getattr(options, k)) for k in kwarg)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/command.py", line 123, in upgrade
    script.run_env()
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/script.py", line 193, in run_env
    util.load_python_file(self.dir, 'env.py')
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/util.py", line 177, in load_python_file
    module = imp.load_source(module_id, path, open(path, 'rb'))
  File "migrations/env.py", line 70, in <module>
    run_migrations_online()
  File "migrations/env.py", line 63, in run_migrations_online
    context.run_migrations()
  File "<string>", line 7, in run_migrations
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/environment.py", line 536, in run_migrations
    self.get_context().run_migrations(**kw)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/migration.py", line 220, in run_migrations
    change(**kw)
  File "migrations/versions/53d21b8f9a8c_add_partial_index_fo.py", line 18, in upgrade
    op.create_index('geocoded', 'locations', ['coordinates'], postgresql_where="locations.coordinates != Null")
  File "<string>", line 7, in create_index
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/operations.py", line 679, in create_index
    self._index(name, table_name, columns, schema=schema, **kw)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/ddl/impl.py", line 160, in create_index
    self._exec(schema.CreateIndex(index))
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/alembic/ddl/impl.py", line 75, in _exec
    conn.execute(construct, *multiparams, **params)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 664, in execute
    params)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 717, in _execute_ddl
    compiled = ddl.compile(dialect=dialect)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/sql/expression.py", line 1906, in compile
    return self._compiler(dialect, bind=bind, **kw)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/schema.py", line 2890, in _compiler
    return dialect.ddl_compiler(dialect, self, **kw)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/engine/interfaces.py", line 787, in __init__
    self.string = self.process(self.statement, **compile_kwargs)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/engine/interfaces.py", line 806, in process
    return obj._compiler_dispatch(self, **kwargs)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 74, in _compiler_dispatch
    return getter(visitor)(self, **kw)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/dialects/postgresql/base.py", line 1120, in visit_create_index
    whereclause = sql_util.expression_as_ddl(whereclause)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/sql/util.py", line 281, in expression_as_ddl
    return visitors.replacement_traverse(clause, {}, repl)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 305, in replacement_traverse
    obj = clone(obj, **opts)
  File "/Users/sth/dev/brockley_analytics/venv/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 291, in clone
    'no_replacement_traverse' in elem._annotations:
AttributeError: 'str' object has no attribute '_annotations'