bugfix: Fixed inappropriate comparison using is

[fazledyn]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Docs change / refactoring / dependency upgrade

Motivation and Context / Related issue

In file mpc.py, there was a comparison that used is operator instead of using ==. In Python, == should be used to compare object.

For example, running the following code will give you the output:

x = []
print(x is [])

False

How Has This Been Tested (if it applies)

Not tested. This is basic logic.

Checklist

• The documentation is up-to-date with the changes I made.
• I have read the CONTRIBUTING document and completed the CLA (see CONTRIBUTING).
• All tests passed, and additional code has been covered with new tests.