input: Write a function to check if a number is within a specified range.
  assert is_in_range(5, 1, 10) == True
  assert is_in_range(15, 1, 10) == False
  assert is_in_range(10, 10, 20) == True
  assert is_in_range(25, 10, 20) == False
  assert is_in_range(-5, -10, 0) == True
output: def is_in_range(number, start, end):
      return start <= number <= end