<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_char_range(self, start, end, increment=None):
 """Get a range of alphabetic characters."""


        increment = int(increment) if increment else 1
        if increment < 0:
            increment = -increment

        # Zero doesn't make sense as an incrementer
        # but like bash, just assume one
        if increment == 0:
            increment = 1

        inverse = start > end
        alpha = _nalpha if inverse else _alpha

        start = alpha.index(start)
        end = alpha.index(end)

        if start < end:
            return (c for c in alpha[start:end + 1:increment])

        else:
            return (c for c in alpha[end:start + 1:increment])