This extension is only made for me, since i just need some custom functions.
Do alt+d to duplicate the line where the cursor is. If you select something, it will duplicate the selected thing.
Do ctrl+c to copy a line if the cursor is not selecting nothing. So if the cursor is somewhere and it isn't selecting some block of text, this will copy the whole line.
If the file is completely empty and there is ONLY the char 't', you can use TAB to automatically create paste your code. To enable or disable this function go to settings and search "Enable Insert Feature", now you should see a setting that asks: "enable the auto insert code after tab when there is only the char 't'?".
To change the text to generate, if the previous setting is enabled, you can go to the settings and search for "Insert Text On Tab", and here you should be able to paste your code block.