I'm using Kali dist so I have already installed Python 2.7, 3.5 and 3.6. Commands 'python' and 'pip' are associated with Python 2.7. But the 'python3' uses Python 3.6 while pip3 is installing packages for Python 3.5.  

When I tried to create an venv:

```
pip3 -p python3.6 virtualenv myenv

```

I've got an error:

```
no such option: -p

```

How can I associate pip3 with Python 3.6 instead of Python 3.5?