小的python计算器错误

def calculate(expression):
    try:
        result = eval(expression)
        return result
    except Exception as e:
        return f"Error: {e}"

# 示例
expression = "2 + 3 * 4"
print(calculate(expression))  # 输出: 14
expression = "2 + 3 *"  # 错误的表达式
print(calculate(expression))  # 输出: Error: malformed node or string

def safe_divide(numerator, denominator):
    try:
        result = numerator / denominator
        return result
    except ZeroDivisionError:
        return "Error: Division by zero is not allowed."

# 示例
print(safe_divide(10, 2))  # 输出: 5.0
print(safe_divide(10, 0))  # 输出: Error: Division by zero is not allowed.

from decimal import Decimal, getcontext

# 设置精度
getcontext().prec = 10

def high_precision_calculate(expression):
    try:
        result = eval(expression, {}, {'Decimal': Decimal})
        return result
    except Exception as e:
        return f"Error: {e}"

# 示例
expression = "Decimal('0.1') + Decimal('0.2')"
print(high_precision_calculate(expression))  # 输出: 0.3