Solution: Missing Number in a Sorted List

def missing_number(lst):
  """
  Finds a missing number from the list which contains sorted numbers from 1 to onwards
  :param lst: List of sorted integers
  :return: Missing number in the sorted list
  """ 
  actual_number = 1 # Grows in ascending order
  for i in lst: # Iterating the entire list
    if i is not actual_number: # If the number in the list is not equal to actual number
      return actual_number # This is the missing number in the list
    actual_number = actual_number + 1 # Incrementing the actual number by 1 
  return -1 # If there is no missing number
# Driver code to test above function
if __name__ == '__main__':
  print(missing_number([1, 2, 4]))
  print(missing_number([1, 2, 3, 4, 6]))
  print(missing_number([2, 3, 4, 5, 6]))
  print(missing_number([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]))