Error on write when assigning inside lambda #554

Error detected while processing function pymode#buffer_post_write..pymode#lint#check:
line   11:
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File ".../python-mode/pymode/lint.py", line 71, in code_check
    env.run('g:PymodeLocList.current().extend', [e._info for e in errors])
  File ".../pymode/environment.py", line 186, in run
    self.prepare_value(a) for a in args
vim.error: Vim(call):E121: Undefined variable: null
Error detected while processing function pymode#buffer_post_write:
line   10:
E171: Missing :endif