fetcher.py crashes with KeyError: 'la'

[schumannd]

this is the error message:

Traceback (most recent call last):
  File "./fetcher.py", line 180, in <module>
    f.start_request()
  File "./fetcher.py", line 122, in start_request
    self._log_lat(uid, str(item["overlay"][uid]["la"]))
KeyError: 'la'

I "fixed" this by checking whether the key exists first. But I'm not sure whether this might break something down the road e.g. in graph.py