input: Write a function to check if a given number is prime. The function should take one integer input. If the input number is prime, it should return True, otherwise, it should return False.
  assert is_prime(17)==True
  assert is_prime(19)==True
  assert is_prime(20)==False
  assert is_prime(97)==True
  assert is_prime(1)==False
output: def is_prime(n):
      if n <= 1:
          return False
      for i in range(2, int(n**0.5) + 1):
          if n % i == 0:
              return False
      return True