``` ``` code block ``` .
code
  block
``` ```` ``` python x = y + 3 ``` .
x = y + 3
```` ```` ``` python if true: x = 3 ``` .
if true:
  x = 3
```` ```` ``` not a code block ``` .

not a code block

```` ```` ``` not a code block .

not a code block

```` ```` ``` hi ``` ``` two ``` .
hi
two
```` Empty code block: ```` ``` ``` .
````