Add function to find upper and lower nibbles with doctests and type hints

bit_manipulation/find_upper_lower_nibble.py

@@ -0,0 +1,29 @@
+def get_nibbles(num: int) -> tuple[int, int]:
+    """
+    Return the upper and lower nibbles of an 8-bit integer.
+
+    A nibble is 4 bits. The lower nibble is the last 4 bits, and
+    the upper nibble is the first 4 bits of the 8-bit number.
+
+    See also: https://en.wikipedia.org/wiki/Nibble
+
+    >>> get_nibbles(100)   # binary: 01100100
+    (6, 4)
+    >>> get_nibbles(255)   # binary: 11111111
+    (15, 15)
+    >>> get_nibbles(0)     # binary: 00000000
+    (0, 0)
+    >>> get_nibbles(1)     # binary: 00000001
+    (0, 1)
+    >>> get_nibbles(240)   # binary: 11110000
+    (15, 0)
+    """
+    lower = num & 0x0F
+    upper = (num & 0xF0) >> 4
+    return upper, lower
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()