input: Write a function to initialize an ArrayContainer class and get the array.
  assert ArrayContainer([1, 2, 3]).get_array() == [1, 2, 3]
  assert ArrayContainer([]).get_array() == []
  assert ArrayContainer([4, 5, 6]).get_array() == [4, 5, 6]
output: class ArrayContainer:
      def __init__(self, array):
          self.array = array
      
      def get_array(self):
          return self.array