The SalesForce Example

Hi there everyone,
I hope I can explain what I am trying to understand.

I am currently in my Graduation Internship, and I am building a analytical web application.

I am looking though code for the SalesForce CRM, and there is a Input I am trying to understand where its coming from for the Indicator for Cases.

Output(“left_cases_indicator”, “children”),
[Input(“cases_df”, “children”)]
pd.read_json(df, orient=“split”)
len(df[(df[“Priority”] == “Low”) & (df[“Status”] == “New”)][“Priority”].index)
return low

I want to know where the ‘cases_df’ is coming from??? cause I can’t find it in the modal where the component id will be.