wash crashes on Python3

I use Python 3.7 (Macos 10.14) and cannot start `wash` after installing via pip.

```bash
bash-5.0$ wash
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/bin/wash", line 11, in
load_entry_point('WASH==1.6.2', 'console_scripts', 'wash')()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pkg_resources/__init__.py", line 487, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2728, in load_entry_point
return ep.load()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2346, in load
return self.resolve()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2352, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/wash.py", line 144
print xml
^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print(xml)?
```

Noting that Python2 will be deprecated come January

Reproduce the `wash` command under Python 3.7 and inspect the installed `wash.py` entry point at the reported `print xml` syntax error. Done means the command starts under Python 3 without this SyntaxError.

Written by the indexing model from the issue text.