Error: "Object of type Series[Unknown] is not callable" on groupby().size().to_frame()

[tvannahl]

Describe the bug
Calling to_frame() on a groupby().size() object causes the reportCallIssue: error: Object of type "Series[Unknown]" is not callable

To Reproduce

Minimal example:

import pandas as pd

data = [
    {"date": "2023-12-01", "val": 12},
    {"date": "2023-12-02", "val": 2},
    {"date": "2023-12-03", "val": 1},
    {"date": "2023-12-03", "val": 10},
]

df = pd.DataFrame(data)
groupby = df.groupby("date")
size = groupby.size()
frame = size.to_frame()
d = frame.reset_index()

Checking:

$ pyright test.py
test.py:14:9 - error: Object of type "Series[Unknown]" is not callable (reportCallIssue)

Please complete the following information:

• OS: MacOS
• OS Version: 14.3.1
• python version: 3.12.2
• version of type checker: 1.1.352
• version of installed pandas-stubs: 2.2.0.240218

Additional context

Issues was not present in pandas-stubs 2.1.4.231227 with pyright 1.1.348

[Dr-Irv]

The error message here is a bit misleading, but the issue happens because the result of size() is a DataFrame or Series, dependent on whether the parameter as_index is False or True, respectively. So we'd need to update the stubs to know whether as_index=False was passed in order to be able to type this correctly.

Closing as it is a duplicate of #652 and related to #203