Difference of Python 2 and Python3 about comparing

Question

a = "SoloLearn"
b = "{}".format("SoloLearn")
print (a , b) #prints SoloeLearn SoloLearn
print (a is b , a == b) #prints True True however in python2 it prints False True

I am willing to see your comments below with the reasons if possible

https://code.sololearn.com/cD855gQgPb5c