@staticmethod
def gen_fibonacci():
    """Yield the next Fibonacci number.

        Based on https://www.python-course.eu/generators.php
        Starts at Fibonacci number 3 (the second 1)

        Yields
        ------
        int
            The next Fibonacci number


        .. versionadded:: 0.3.0
        .. versionchanged:: 0.3.6
            Encapsulated in class

        """
    num_a, num_b = 1, 2
    while True:
        yield num_a
        num_a, num_b = num_b, num_a + num_b
