Python scripts: SyntaxWarnings in comparisons in Python3

[jenisys]

Describe the bug FSeam python scripts cause various Python3 syntax warnings in comparisons related to:

• A is B used instead of A == B
• A is not B used instead of A != B

AFFECTED FILES:

• FSeam/Generator/CppHeaderParser.py
• FSeam/Generator/FSeamerFile.py

To Reproduce Steps to reproduce the behavior:

1. Install FSeam project as package with cmake to CMAKE_INSTALL_PREFIX=/usr/local
2. Use FSeam_tutorial project and build it with cmake
3. The following Python SyntaxWarnings occur during cmake build phase:

$ cmake --build .
[4/32] Generating FSEAM code for /.../FSeam_tutorial/Static-Free_FunctionMock_Example/include/FreeFunction.h
/usr/local/bin/FSeamerFile.py:426: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  return sb + ee if sm is not "" and em is not "" else content
/usr/local/bin/FSeamerFile.py:426: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  return sb + ee if sm is not "" and em is not "" else content
/usr/local/bin/CppHeaderParser.py:225: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if namespaceSeparator is 2:
...
# -- OCCURS: Several times.

Expected behavior Use the correct Python comparison operators. Use "==" instead of "is" and "!=" instead of "is not".

Desktop (please complete the following information):

• OS: macOS
• Python: 3.8
• cmake: 3.18.0