Absent of python 3.8 feature "assignment expression"

[JackAllTrades-MoN]

Summary

Assignment expression (https://www.python.org/dev/peps/pep-0572/) is not yet available on language-python.

• result on ghci

*PyParser> import qualified Language.Python.Version3.Parser as PyParser
*PyParser> PyParser.parseExpr "print(x := 2)" ""
Left (UnexpectedToken (ColonToken {token_span = SpanPoint {span_filename = "", span_row = 1, span_column = 9}}))

• example on python3.8

>>> print(x := 2)
2

Note

If you don't mind, I'll send a PR of this issue later. Please, check if it looks ok.

[bjpop]

Thanks @JackAllTrades-MoN.

PR would be appreciated. If possible, please include test cases as well.

Cheers!