Support for python `lambda`

[Smit-create]

Lambda expressions in python don't support annotations. See: https://www.python.org/dev/peps/pep-3107/#lambda
They can be simply mapped to ASR function but still will be a difficult task without knowing the argument type.

[certik]

Interesting. We might support lambdas once we have templates, without type annotation. Until then, we probably would require to simply create a local function and use it instead of a lambda.