有症状地 destruct 了Python中的regex

我有代码:

import re
import math
#from sympy import * # breaks?
#x, y, z = symbols('x y z')
#init_printing(use_unicode=True)


def evaluate_expression(expr, variables):
    # Evaluate the expression using eval(), and provide the variables dictionary
    return eval(expr, variables)

def main():
    tools = """
<<<[eval("5"),a_x]>>>
<<<[eval("5+a_x"),ans]>>>
"""

    variables = {}
    lines = tools.strip().split("\n")

    for line in lines:
        # Extract the inner array using regular expression
        match = re.search(r'<<<\[(.*?),(\w+)\]>>>', line)
        if match:
            # Extract expression and variable name
            expr = match.group(1)
            var_name = match.group(2)

            # Evaluate expression
            value = evaluate_expression(expr, variables)

            # Update variables dictionary
            variables[var_name] = value

            # Check if 'ans' is defined
            if 'ans' in variables:
                print("ans =", variables['ans'])
                break

if __name__ == "__main__":
    main()

如果我不导入symy，它运行得很好，但如果我确实导入symy，它就会崩溃，重新搜索不再存在，无论我给变量命名什么.我不明白吗？