这段代码有几处不合规

一段十一行的示例代码：

 1  import os
 2
 3  def CalcTotal(items):
 4      total = 0␣␣␣
 5      for i in items:
 6          total = total + i␣␣␣
 7      unused = 42
 8      return total
 9
10  def calcAverage(items, weights, extra_config_value):
11      return CalcTotal(items) / len(items)

（␣ 表示一个看不见的行尾空格）

按四条规则检查：行尾空格、行太长、函数名不是小写下划线、变量赋了值却没用过。运行下面这段程序：

import re

def is_snake(name):
    return re.fullmatch(r"[a-z_][a-z0-9_]*", name) is not None

import re

def lint(src, maxlen=45):
    out = []
    for i, l in enumerate(src, 1):
        if l != l.rstrip():
            out.append((i, "E101"))
        if len(l) > maxlen:
            out.append((i, "E102"))
        m = re.match(r"def\s+(\w+)\s*\(", l)
        if m and not is_snake(m.group(1)):
            out.append((i, "E201"))
    for i, l in enumerate(src, 1):
        m = re.match(r"\s*(\w+)\s*=\s*", l)
        if not m:
            continue
        name = m.group(1)
        used = any(re.search(r"\b" + name + r"\b", x)
                   for j, x in enumerate(src, 1)
                   if j != i and not re.match(r"\s*" + name + r"\s*=", x))
        if not used:
            out.append((i, "E301"))
    return sorted(out)

src = ['import os',
       '',
       'def CalcTotal(items):',
       '    total = 0   ',
       '    for i in items:',
       '        total = total + i   ',
       '    unused = 42',
       '    return total',
       '',
       'def calcAverage(items, weights, extra_config_value):',
       '    return CalcTotal(items) / len(items)']
print(len(lint(src)))