def decode_command(command: str) -> str: stack: list = [] current_num: int = 0 current_str: str = '' for char in command: # вместо isdigit() сделать проверку через string.digits! if char.isdigit(): current_num = current_num * 10 + int(char) elif char == '[': stack.append((current_str, current_num)) current_str, current_num = '', 0 elif char == ']': prev_str, prev_num = stack.pop() current_str = prev_str + prev_num * current_str else: current_str += char return current_str

This function decodes a command that is encoded in a specific format and returns the decoded string. The encoding format involves using numbers to indicate the repetition of a substring enclosed in square brackets.

Here's how the function works:

1. It initializes an empty stack, a current number variable, and a current string variable.
2. It iterates through each character in the input command.
3. If the character is a digit, it updates the current number by multiplying it by 10 and adding the integer value of the character.
4. If the character is '[', it pushes the current string and number onto the stack and resets the current string and number.
5. If the character is ']', it pops the previous string and number from the stack, and updates the current string by repeating the previous string the specified number of times.
6. If the character is neither a digit nor '[', it appends the character to the current string.
7. Finally, it returns the fully decoded string.

This function effectively decodes an encoded command using a stack to keep track of nested repetitions.