code: def prime_check(n):
      
  
      if n <= 1:
          return False
      if n == 2 or n == 3:
          return True
      if n % 2 == 0 or n % 3 == 0:
          return False
      j = 5
      while j * j <= n:
          if n % j == 0 or n % (j + 2) == 0:
              return False
          j += 6
      return True
docs: Return True if n is a prime number
      Else return False.