如何使用Python正则表达式进行代码复杂度分析

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import redef parse_code(code):    stack = []    depth = 0    for line in code.split(""):        if re.match(".*:s*$", line):            stack.append("block")            depth += 1        elif re.match("def.*:", line):            stack.append("function")            depth += 1        elif re.match(".*s(if|else|elif|for|while)s.*:", line):            depth += 1        while stack and stack[-1] != "block":            stack.pop()            depth -= 1        if stack:            print("{:>2}: {}".format(depth, line.strip()))        if re.match("^s*$", line):            while stack and stack[-1] != "block":                stack.pop()                depth -= 1    return depth

import redef count_paths(code):    paths = []    visited = set()    def walk(path):        if path[-1] in visited:            return        visited.add(path[-1])        if re.match(".*:s*$", path[-1]):            paths.append(list(path))        for i, line in enumerate(code.split("")):            if line == path[-1]:                for j in range(i+1, len(code.split(""))):                    if line in code.split("")[j]:                        walk(path + [code.split("")[j]])    for i, line in enumerate(code.split("")):        if re.match(".*:s*$", line):            walk([line])            break    return len(paths)