问题描述:
Write a python function to count the upper case characters in a given string.

测试用例:
["assert upper_ctr('PYthon') == 1", "assert upper_ctr('BigData') == 1", "assert upper_ctr('program') == 0"]

生成的代码:
def upper_ctr(s):
    count = 0
    for char in s:
        if char.isupper():
            count += 1
    return count

# Test cases
assert upper_ctr('PYthon') == 2
assert upper_ctr('BigData') == 1
assert upper_ctr('program') == 0