input: Write a function to determine if a number provided by the user is prime or not. If the number is prime, return True, else return False. If the number is less than or equal to 1, return False.
  assert is_prime(17) == True
  assert is_prime(4) == False
  assert is_prime(1) == False
  assert is_prime(-5) == False
  assert is_prime(11) == True
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