How to change part of the value string in Python Dictionary?

[sbabu]

This is on Jupiter

!s. + 2 x TAB

Error:
's.' is not recognized as an internal or external command,
operable program or batch file.

This is Thonny Command prompt
>>> s = 123
>>> s.
File "<stdin>", line 1
s.
^
SyntaxError: invalid syntax
>>> !s.
File "<stdin>", line 1
!s.
^
SyntaxError: invalid syntax
>>>