def count_distinct_characters(string: str) -> int:
    """ Given a string, find out how many distinct characters (regardless of case) does it consist of
    >>> count_distinct_characters('xyzXYZ')
    3
    >>> count_distinct_characters('Jerry')
    4
    
    Example solution:
    # line 1
    st = set()
    # line 2
    for char in string:
        # line 3
        st.add(char)
    # line 4
    return len(st)
    
    """
    # Please print out which line of the above program contains an error. E.g. if the bug is on line 4 then print 4
    # END OF CONTEXT
    print("2")
    # END OF SOLUTION


METADATA = {
    'author': 'jt',
    'dataset': 'test'
}


def check(candidate):
    import io
    from contextlib import redirect_stdout

    f = io.StringIO()
    with redirect_stdout(f):
        candidate('')
    out = f.getvalue().strip('\n')

    assert "2" == out
    for i in range(0, 10):
        if i != 2:
            assert str(i) != out

if __name__ == '__main__':
    check(count_distinct_characters)
