Update document for group selection

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (d27cdb4) 97.72% compared to head (e709736) 97.72%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #508 +/- ## ======================================= Coverage 97.72% 97.72% ======================================= Files 7 7 Lines 969 969 ======================================= Hits 947 947 Misses 22 22 ``` | Flag | Coverage Δ | | |---|---|---| | Python | `97.72% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://app.codecov.io/gh/abess-team/abess/pull/508?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team) | Coverage Δ | | |---|---|---| | [python/abess/bess\_base.py](https://app.codecov.io/gh/abess-team/abess/pull/508?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team#diff-cHl0aG9uL2FiZXNzL2Jlc3NfYmFzZS5weQ==) | `98.87% <ø> (ø)` | |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.