gen_fn.py

# Define the `char_range` generator here
def char_range(start, stop, step=1):
    stop_modifier = 1
    start_code = ord(start)
    stop_code = ord(stop)

    if start_code > stop_code:
        step *= -1
        stop_modifier *= -1

    for value in range(start_code,stop_code + stop_modifier,step):
        yield chr(value)
    

# Tests to verify the implementation of char_range
# *Do not modify
##################################################

# Ensure that `char_range` is a generator function
from inspect import isgeneratorfunction

assert isgeneratorfunction(
    char_range
), f"Expected char_range to be a generator function but was not."
print(char_range)
# Ensure that the result *does* includes the stop character
assert list(char_range("a", "e")) == [
    "a",
    "b",
    "c",
    "d",
    "e",
], f"Expected ['a', 'b', 'c', 'd', 'e'] but got {repr(list(char_range('a', 'e')))}"
print(char_range("a","e"))
# Iterate backwards if the start code point is higher than the stop code point

assert list(char_range("e", "a")) == [
    "e",
    "d",
    "c",
    "b",
    "a",
], f"Expected ['e', 'd', 'c', 'b', 'a'] but got {repr(list(char_range('e', 'a')))}"
print(char_range('e','a'))
# Properly step if a step value is provided

assert list(char_range("a", "e", 2)) == [
    "a",
    "c",
    "e",
], f"Expected ['a', 'c', 'e'] but got {repr(list(char_range('a', 'e', 2)))}"
print(char_range('a','e',2))
# Step properly if the start code point is higher than the stop code point

assert list(char_range("e", "a", 2)) == [
    "e",
    "c",
    "a",
], f"Expected ['e', 'c', 'a'] but got {repr(list(char_range('e', 'a', 2)))}"
print(char_range('e','a',2))