def _find_closing_brace(string, start_pos):
    """Finds the corresponding closing brace after start_pos."""
    bracks_open = 1
    escaped = False
    for idx, char in enumerate(string[start_pos:]):
        if char == '(':
            if not escaped:
                bracks_open += 1
        elif char == ')':
            if not escaped:
                bracks_open -= 1
            if not bracks_open:
                return start_pos + idx + 1
        if char == '\\':
            escaped = not escaped
        else:
            escaped = False