Basic Python question

[j.crater]

The output I get after running your code is:

Output:
[ mystring ]

It is because print function's default separator is a whitespace. If you want to change the separator, you can specify it explicitly:

print("[",a,"]", sep='')

An alternative you can use, which is also more generic, is to format the string (with format method):

print("[{}]".format(a))