Help needed on code notation

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<Below this line, add a link to the EXACT exercise that you are stuck at. The query string (? and beyond) may be truncated.>

<In what way does your code behave incorrectly? Include ALL error messages.>
This is not so much related to any exercise in general.
I have a problem understanding when does the method goes before the object such as str()/len() etc. and when does the object come before the method such as list.append()/str.upper().

Is there any guideline as to which comes before which?
<What do you expect to happen instead?>

```python
<do not remove the three backticks above>

In this case that is simple. No, there is no guideline as neither case is applicable. What reading can you refer us to so that we may be better apprised of the same information?