I was performing some mutation testing on Funcy, and I noticed that the logging function calls with keywords are not tested.
For example, a function call like this is not tested:

def f(x, y=2):
   return x + y

This causes the following part of the code not to be tested for its functionality:
debug.py: line 230-231:

kwargs_repr = ('%s=%s' % (key, smart_repr(value, repr_len))
                   for key, value in call._kwargs.items())

This line is covered, but its functionality still needs to be tested.
I'll add a test case for it in a pull request.