`static` functions

[iWas-Coder]

Description

Please, include a summary of the changes and which issue(s) is/are fixed. Also include relevant motivation and context. Lastly, list any dependencies that are required for this change.

Issues:

• closes #56

  Motivation and context:

• (...)

  Dependencies:

• N/A

  Tests:

• Ran all tests (make check) in both debug and release modes.

Type of change

• [ ] Bug fix (non-breaking change which fixes one or multiple issues).
• [x] New feature (non-breaking change which adds functionality).
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected).

Checklist:

• [x] I've read and comply with the contributing guidelines.
• [ ] I've tested my changes for new features and regressions on all supported operating systems.
• [ ] I've made corresponding changes to the documentation.
• [ ] I've checked my changes for any broken behaviour and/or any unjustified performance hits.
• [x] My changes generate no new warnings.
• [ ] I've added tests that prove my fix is effective or that my feature works.
• [x] New and existing tests pass locally with my changes.