input: Write a python function that accepts a string composed of brackets. Return True if each opening bracket has a matching closing bracket. Otherwise, return False.
  assert balanced_brackets("()")
  assert balanced_brackets("(()())")
  assert balanced_brackets("()()(()())()")
  assert balanced_brackets("()()((()()())())(()()(()))")
  assert not balanced_brackets("((()())))")
  assert not balanced_brackets(")(()")
  assert not balanced_brackets("(")
  assert not balanced_brackets("((((")
  assert not balanced_brackets(")")
  assert not balanced_brackets("(()")
  assert not balanced_brackets("()()(()())())(()")
  assert not balanced_brackets("()()(()())()))()")
output: def balanced_brackets(s):
      stack = []
      for char in s:
          if char == '(':
              stack.append(char)
          elif char == ')':
              if not stack:
                  return False
              stack.pop()
      return not stack