input: Write a function to check if a given number is prime.
  
  assert primeCheck(2)==True
  assert primeCheck(3)==True
  assert primeCheck(4)==False
  assert primeCheck(11)==True
  assert primeCheck(15)==False
output: def primeCheck(n):
      if n <= 1:
          return False
      for i in range(2, int(n**0.5) + 1):
          if n % i == 0:
              return False
      return True