Rgb Cmyk Conversion

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```def rgb_to_cmyk(r_input: int, g_input: int, b_input: int) -> tuple[int, int, int, int]:
"""
Simple RGB to CMYK conversion. Returns percentages of CMYK paint.
https://www.programmingalgorithms.com/algorithm/rgb-to-cmyk/

Note: this is a very popular algorithm that converts colors linearly and gives
only approximate results. Actual preparation for printing requires advanced color
conversion considering the color profiles and parameters of the target device.

>>> rgb_to_cmyk(255, 200, "a")
Traceback (most recent call last):
...
ValueError: Expected int, found (<class 'int'>, <class 'int'>, <class 'str'>)

>>> rgb_to_cmyk(255, 255, 999)
Traceback (most recent call last):
...
ValueError: Expected int of the range 0..255

>>> rgb_to_cmyk(255, 255, 255)  # white
(0, 0, 0, 0)

>>> rgb_to_cmyk(128, 128, 128)  # gray
(0, 0, 0, 50)

>>> rgb_to_cmyk(0, 0, 0)    # black
(0, 0, 0, 100)

>>> rgb_to_cmyk(255, 0, 0)  # red
(0, 100, 100, 0)

>>> rgb_to_cmyk(0, 255, 0)  # green
(100, 0, 100, 0)

>>> rgb_to_cmyk(0, 0, 255)    # blue
(100, 100, 0, 0)
"""

if (
not isinstance(r_input, int)
or not isinstance(g_input, int)
or not isinstance(b_input, int)
):
msg = f"Expected int, found {type(r_input), type(g_input), type(b_input)}"
raise ValueError(msg)

if not 0 <= r_input < 256 or not 0 <= g_input < 256 or not 0 <= b_input < 256:
raise ValueError("Expected int of the range 0..255")

# changing range from 0..255 to 0..1
r = r_input / 255
g = g_input / 255
b = b_input / 255

k = 1 - max(r, g, b)

if k == 1:  # pure black
return 0, 0, 0, 100

c = round(100 * (1 - r - k) / (1 - k))
m = round(100 * (1 - g - k) / (1 - k))
y = round(100 * (1 - b - k) / (1 - k))
k = round(100 * k)

return c, m, y, k

if __name__ == "__main__":
from doctest import testmod

testmod()
```