input: Write a function to determine if a number is prime or not. The function should take an integer as input and return True if the number is prime, otherwise return False.
  assert is_prime(17) == True
  assert is_prime(4) == False
  assert is_prime(29) == True
  assert is_prime(1) == False
  assert is_prime(-3) == 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