Enhancement: Error messages not very human friendly - should be very specific why something failed (user error vs system error)

[grimen]

Example:

[2019-01-16 20:54:39 -0500] [11635] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "/Users/grimen/.pyenv/versions/3.6.6/envs/3.6.6-default/lib/python3.6/site-packages/attributedict/collections.py", line 223, in __getattr__
    return self.__getitem__(key)
  File "/Users/grimen/.pyenv/versions/3.6.6/envs/3.6.6-default/lib/python3.6/site-packages/attributedict/collections.py", line 165, in __getitem__
    result = self.__dict__.__getitem__(key)
KeyError: 'nn'