info routine to display info about the ObsSequence

[hkershaw-brown]

repl and str also

fixes #92

Example:

>>> import pydartdiags.obs_sequence.obs_sequence as obsq
>>> obs_seq = obsq.ObsSequence(file=None)
>>> obs_seq
ObsSequence(file=None)
>>> print(obs_seq)
ObsSequence: None
  obs types : []
  copies    : []
  n_obs     : 0
>>> obs_seq.info()
Non-routines (data attributes):
  - all_obs: []
  - copie_names: []
  - default_composite_types: /Users/hkershaw/DART/siparcs/2026/pyDARTdiags/src/pydartdiags/obs_sequence/composite_types.yaml
  - df: DataFrame(0, 0)
  - file: None
  - loc_mod: None
  - n_copies: 0
  - n_non_qc: 0
  - n_qc: 0
  - non_qc_copie_names: []
  - qc_copie_names: []
  - reverse_types: {}
  - reversed_vert: {'undefined': -2, 'surface (m)': -1, 'model level': 1, 'pressure (Pa)': 2, 'height (m)': 3, 'scale height': 4}
  - seq: []
  - synonyms_for_obs: ['NCEP BUFR observation', 'AIRS observation', 'GTSPP observation', 'SST observation', 'observations', 'WOD observation']
  - types: {}
  - vert: {-2: 'undefined', -1: 'surface (m)', 1: 'model level', 2: 'pressure (Pa)', 3: 'height (m)', 4: 'scale height'}

Routines (methods/functions):
  - composite_types
  - create_header
  - create_header_from_dataframe
  - has_assimilation_info
  - has_posterior
  - info
  - join
  - possible_vs_used
  - select_by_dart_qc
  - select_used_qcs
  - update_attributes_from_df
  - write_obs_seq

This example is a black obs seq so boring.

[hkershaw-brown]

in print(obs_seq) also want loc_mod?

edit added loc mod

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.94%. Comparing base (4cea059) to head (46463cc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #133      +/-   ##
==========================================
+ Coverage   64.13%   64.94%   +0.81%     
==========================================
  Files           5        5              
  Lines        1118     1141      +23     
==========================================
+ Hits          717      741      +24     
+ Misses        401      400       -1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[mjs2369]

Would it be worth it to test if more stuff than this is in the return from info()? Even in an empty obs_seq, as shown in the body text of this PR, there should be the full set of data attributes and routines

[hkershaw-brown]

yes this is exactly what our intern Ira is hitting.
Right now, totally blank.
Should be the required columns. I was thinking it would be good to have Ira do the fix and pull request for a "from scratch" obs seq.

[hkershaw-brown]

hang on I am mixing up two issues

The test is using
obj = obsq.ObsSequence(file=None)
which is really minimal (i.e. no info). When really it should be the minimum columns (which is what it would be cool to have Ira add).

[mjs2369]

This PR is good to go; Ira expected to expand on this by testing for the minimum columns returned by info