old_contents: # List manipulation
  
  sample = [3,7,8,10,22,1,7,-4]
  
  print("initial list:", sample)
  
  # Now let's APPEND to the list
  sample.append(23)
  print("after append:", sample)
  
  # INSERT at a specific location in the 0-based list
  sample.insert(4, 99) # index `4` is 22
  print("after insert:", sample)
  
  '''
  Output:
  initial list: [3, 7, 8, 10, 22, 1, 7, -4]
  after append: [3, 7, 8, 10, 22, 1, 7, -4, 23]
  after insert: [3, 7, 8, 10, 99, 22, 1, 7, -4, 23]
  
  '''
  
  # REMOVE the first occurrence from list, will throw an ERROR if not found
  sample.remove(6) # will generate an error
  
  '''
  Output:
  
  ValueErrorTraceback (most recent call last)
  <ipython-input-6-80a5dc861761> in <module>()
       14 
       15 # REMOVE the first occurrence from list, will throw an ERROR if not found
  ---> 16 sample.remove(6)
  
  ValueError: list.remove(x): x not in list
  
  '''
  
  # Now REMOVE an item
  sample.remove(7)
  print("after remove:", sample)
  
  # after remove: [3, 8, 10, 99, 22, 1, 7, -4, 23]
  
new_contents: # List manipulation
  
  sample = [3,7,8,10,22,1,7,-4]
  
  print("initial list:", sample)
  
  # Now let's APPEND to the list
  sample.append(23)
  print("after append:", sample)
  
  # INSERT at a specific location in the 0-based list
  sample.insert(4, 99) # index `4` is 22
  print("after insert:", sample)
  
  '''
  Output:
  initial list: [3, 7, 8, 10, 22, 1, 7, -4]
  after append: [3, 7, 8, 10, 22, 1, 7, -4, 23]
  after insert: [3, 7, 8, 10, 99, 22, 1, 7, -4, 23]
  
  '''
  
  # REMOVE the first occurrence from list, will throw an ERROR if not found
  sample.remove(6) # will generate an error
  
  '''
  Output:
  
  ValueErrorTraceback (most recent call last)
  <ipython-input-6-80a5dc861761> in <module>()
       14 
       15 # REMOVE the first occurrence from list, will throw an ERROR if not found
  ---> 16 sample.remove(6)
  
  ValueError: list.remove(x): x not in list
  
  '''
  
  # Now REMOVE an item
  sample.remove(7)
  print("after remove:", sample)
  
  # More operations....
  print("what value is at index 5?", sample[5])
  print("where is 99?", sample.index(99))
  
  print("How many 7s are in the list after we removed one?", sample.count(7))
  print("How many 6s in the list?", sample.count(6))
  
  '''
  Output:
  after remove: [3, 8, 10, 99, 22, 1, 7, -4, 7, 23]
  what value is at index 5? 1
  where is 99? 3
  How many 7s are in the list after we removed one? 2
  How many 6s in the list? 0
  '''
  
  
subject: Update lists.py