Want to know something new!

Question

We know that in python this
print("{:#>5}".format(9))
will print 4 '#'s and 9 at end!
I want to do this:
a=5
print("{:#>a}".format(9))
How to use it like that?

Answer 1

Today i learn something new.
a=5
a=('{:#>'+str(a)+'}')
print(a.format(9))

Answer 2

Alternative to Maninder Singh .
a=5
print(('{:#>'+str(a)+'}').format(9))
#This will not change the value of a!
#Thanks in between to give the idea!