Bracket nesting correctness check

It is necessary to write a function areBracketsBalanced that determines whether brackets are correctly distributed in the given string expr. The string only allows characters of round, square, and curly brackets – ()[]{}. The function should return True when each opening bracket has a corresponding closing bracket in the correct order, and False otherwise.

def areBracketsBalanced(expr):
    stack = []

    for char in expr:
        if char in ["(", "{", "["]:
            stack.append(char)
        else:
            if not stack:
                return False
            current_char = stack.pop()
            if current_char == "(":
                if char != ")":
                    return False
            if current_char == "{":
                if char != "}":
                    return False
            if current_char == "[":
                if char != "]":
                    return False

    return not stack