Currently repr of doesn't contain much of information besides that it is a lambda.
lambda x: x**2 <function <lambda> at 0x7f3479b74488>
All lambdas have the same repr, different only by unreadable hexadecimal address. What if include the signature and the expression of the lambda in its repr?
lambda x: x**2 <lambda x: x**2>
This would return an old feature of Python 0.9.1 (https://twitter.com/dabeaz/status/934835068043956224). Repr of function could contain just the signature. <function foo(bar, baz)> But there is a problem with default values. Their reprs can be very long, especially in the following case with mutable default value: def foo(x, _cache={}): try: return _cache[x] except KeyError: pass _cache[x] = y = expensive_calculation(x) return y Maybe the placeholder should be always used instead of default values.