Why is the variable `input` often marked special in Python syntax markers?
In many syntax highlighters (e.g. jupyter notebooks) the variable input is highlighted in python. Is there a reason for this? I've avoided using input as a variablename because I thought it did something special internally.

I'm asking because pytorch often uses "input" as a variable in their tutorials. 

input is a function.
This will happen as well with for example list.

It is recommended not to overwrite the build-in functions with own variables.
