input: Write a function to find the common elements between two lists and return them as a new list. If the input lists are empty, return an empty list.
  def common_elements(list1, list2): 
      common_list=[]
      for element in list1: 
          if element in list2: 
              common_list.append(element) 
      return common_list
    
  assert common_elements([1, 2, 3, 4, 8], [2, 6, 8, 10])==[2, 8]
  assert common_elements([1, 3, 5, 7], [2, 4, 6, 8])==[]
  assert common_elements([], [2, 4, 6, 8])==[]
  assert common_elements([1, 2, 3, 4, 5], [])==[]
  assert common_elements([1, 2, 3], [3, 2, 1])==[1, 2, 3]
output: def common_elements(list1, list2): 
      common_list=[]
      for element in list1: 
          if element in list2: 
              common_list.append(element) 
      return common_list