Mypy plugin doesn't honor the python 2.7 option

I installed the mypy-plugin.jar on PyCharm 2018.1, and I am trying to run `mypy` on some python 2.7 code with the 2.7 interpreter and PATH suffix configured correctly.

`dmypy start -- --python-version=2.7; dmypy check test_api.py
`
or
`dmypy start -- --py2; dmypy check test_api.py`

I see this:

> test_api:95: error: Missing parentheses in call to 'print'. Did you mean print(out, err)?

This appears to be a python3 error.

Appears that the` 'py2' `option is not being honored. I know this because running the same from command line using the option gives me different warnings (specific to python 2.7).

E.g., `mypy --py2 --ignore-missing-imports test_api.py`

> test_api.py:16: error: Argument 1 to "join" has incompatible type "Optional[str]"; expected "str"

Has anyone tried this? It is easily reproducible. Am I missing something here?