Modernize Python 2 code to get ready for Python 3

[cclauss]

• Use print() function in both Python 2 and Python 3
  • Legacy print statements are syntax errors in Python 3 but print() function works as expected in both Python 2 and Python 3.
• Old style exceptions --> new style for Python 3
  • Old style exceptions are syntax errors in Python 3 but new style exceptions work as expected in both Python 2 and Python 3.

[LostSymbol]

Thank you for your support!