What does *** mean in Python -3?

Question

I was going through an Image Processing Python Script available at http://www.ma.iup.edu/~hedonley/python/ and came across the operator *** .

What does it mean? I know * means multiplication and ** means exponentiation.

Answer 1

It does not mean anything:

Python 3.6.4 (default, Feb 27 2018, 22:13:22)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> foo = ***
  File "<stdin>", line 1
    foo = ***
           ^
SyntaxError: invalid syntax
>>>

Most likely, in the context of the article you linked , it is intended to be a placeholder.