input: Write a function to check if a number is within a given range.
  assert check_range(10, 10, 20) == True
  assert check_range(5, 1, 10) == True
  assert check_range(15, 10, 20) == True
  assert check_range(25, 10, 20) == False
  assert check_range(10, 11, 20) == False
output: def check_range(num, start, end):
      return start <= num <= end