All Upper II

All Upper II

Check if a given string has all symbols in upper case. If the string is empty or doesn't have any letter in it - function should return False.

Input: A string (str).

Output: A logic value (bool).

Examples:

assert is_all_upper("ALL UPPER") == True
assert is_all_upper("all lower") == False
assert is_all_upper("mixed UPPER and lower") == False
assert is_all_upper("") == False

Precondition: a-z, A-Z, 1-9 and spaces.

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