如何以编程方式检查项目中是否使用了变量？

import ast

def check_variables(code):
    tree = ast.parse(code)
    variables = set()
    for node in ast.walk(tree):
        if isinstance(node, ast.Name):
            variables.add(node.id)
    return variables

code = """
a = 1
b = 2
c = a + b
print(c)
"""

variables = check_variables(code)
print(variables)

{'a', 'b', 'c'}

const code = `
let a = 1;
let b = 2;
let c = a + b;
console.log(c);
`;

const eslint = require('eslint');
const parser = require('@babel/eslint-parser');

const parserOptions = {
    ecmaVersion: 2020,
    sourceType: 'module',
    ecmaFeatures: {
        jsx: true,
    },
};

const linter = new eslint.ESLint({
    parser: parser,
    parserOptions: parserOptions,
});

linter.verify(code, {
    rules: {
        'no-unused-vars': 'error',
    },
}).forEach(message => {
    console.log(message);
});

{
  ruleId: 'no-unused-vars',
  severity: 2,
  message: 'a is defined but never used',
  line: 2,
  column: 5,
  nodeType: 'Identifier',
  source: 'let a = 1;'
}
{
  ruleId: 'no-unused-vars',
  severity: 2,
  message: 'b is defined but never used',
  line: 3,
  column: 5,
  nodeType: 'Identifier',
  source: 'let b = 2;'
}