本函数可找出列表中缺失的数，方法如下：1. 创建列表中所有数的集合；2. 创建从 1 到列表中最大数的所有数的列表；3. 通过从所有数的列表中减去集合中的数，找出缺失的数。

def find_missing_numbers(nums):
  """
  Finds all the missing numbers in a list of integers.

  Args:
    nums: A list of integers.

  Returns:
    A list of all the missing numbers in the list.
  """

  # Create a set of all the numbers in the list.
  num_set = set(nums)

  # Create a list of all the numbers from 1 to the maximum number in the list.
  max_num = max(nums)
  num_list = list(range(1, max_num + 1))

  # Find the missing numbers by subtracting the set of numbers in the list from
  # the list of all numbers.
  missing_nums = list(set(num_list) - num_set)

  return missing_nums