input: Write a function to find and return the factors of a given number.
  assert find_factors(10) == [1, 2, 5, 10]
  assert find_factors(25) == [1, 5, 25]
  assert find_factors(11) == [1, 11]
output: def find_factors(n):
      factors = []
      for i in range(1, n + 1):
          if n % i == 0:
              factors.append(i)
      return factors