Write two fucntions <font face="Courier New">star(n)</font> and
<font face="Courier New">blank(n)</font>, which will return a string
of n stars and a string of n blanks, respectively.
Test your functions with the following main program.
<PRE>
<CODE>
def main():
    k = 6
    for i in range(k-1):
        print(star(k-i), blank(2*i+1), star(k-i), sep='' )
    for i in range(k-1, -1, -1):
        print(star(k-i), blank(2*i+1), star(k-i), sep='' )

main()
</CODE>
</PRE>


<HR>
Note: the expected output might be
<PRE>
<CODE>
****** ******
*****   *****
****     ****
***       ***
**         **
*           *
**         **
***       ***
****     ****
*****   *****
****** ******
</CODE>
</PRE>