def check_styling(lines):
    (ifndef_symbol, ifndef_line) = get_ifndef_symbol(lines)
    (_, define_line) = get_define_symbol(lines)
    if (abs((ifndef_line - define_line)) != 1):
        return '#ifndef and #define lines are not subsequent'
    if (lines[(ifndef_line - 1)].strip() != ''):
        return 'Preceding line is not empty'
    if (lines[(define_line + 1)].strip() != ''):
        return 'Following line is not empty'
    if (not (lines[(- 1)][(- 1)] in ['\n', '\r'])):
        return 'Last line must end with a newline'
    for l in lines[2:23]:
        if (l[0] != ' '):
            return 'Copyright header must be indented'
    if (ifndef_symbol != ifndef_symbol.upper()):
        return 'Include guard is not all upper case'
    return ''
def check_styling(lines):
    (ifndef_symbol, ifndef_line) = get_ifndef_symbol(lines)
    (_, define_line) = get_define_symbol(lines)
    if (abs((ifndef_line - define_line)) != 1):
        return '#ifndef and #define lines are not subsequent'
    if (lines[(ifndef_line - 1)].strip() != ):
        return 'Preceding line is not empty'
    if (lines[(define_line + 1)].strip() != ):
        return 'Following line is not empty'
    if (not (lines[(- 1)][(- 1)] in ['\n', '\r'])):
        return 'Last line must end with a newline'
    for l in lines[2:23]:
        if (l[0] != ' '):
            return 'Copyright header must be indented'
    if (ifndef_symbol != ifndef_symbol.upper()):
        return 'Include guard is not all upper case'
    return 