python_install fails for multiple packages

[zirkov]

OS: Ubuntu
Release: Bionic

When 2 or more packages are required to be installed through python_install: [package1, package2] Ansible yields an error during run:

failed: [sm-ubuntu-02] (item=2.7) => {"changed": false, "cmd": ["/usr/local/bin/pip2.7", "install", "pyyaml requests"], "item": 2.7, "msg": "\n:stderr: DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.\nInvalid requirement: 'pyyaml requests'\n\n"}
failed: [sm-ubuntu-02] (item=3.6) => {"changed": false, "cmd": ["/usr/local/bin/pip3.6", "install", "pyyaml requests"], "item": 3.6, "msg": "\n:stderr: Invalid requirement: 'pyyaml requests'\n\n"}

Looking at this: "cmd": ["/usr/local/bin/pip3.6", "install", "pyyaml requests"] and the fact that 'pyyaml requests' is considered a single request, it seems that the space-separated string is somehow passed as a single parameter to pip install