add print functions

[clarkliming]

close #35

[github-actions]

Code Coverage Summary

Filename                     Stmts    Miss  Cover    Missing
-------------------------  -------  ------  -------  -----------------------
R/bias.R                        11       0  100.00%
R/predict_couterfactual.R       47       0  100.00%
R/prediction_cf.R                3       0  100.00%
R/robin_glm.R                   27       0  100.00%
R/treatment_effect.R            99      28  71.72%   30, 43, 68, 80, 174-197
R/utils.R                       21       1  95.24%   16
R/variance_anhecova.R           45      19  57.78%   30, 45-46, 59, 65-80
R/variance_hc.R                  9       0  100.00%
TOTAL                          262      48  81.68%

Diff against main

Filename                     Stmts    Miss  Cover
-------------------------  -------  ------  --------
R/predict_couterfactual.R       +1       0  +100.00%
R/treatment_effect.R           +27     +24  -22.73%
TOTAL                          +28     +24  -8.06%

Results for commit: 70bd597

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

 1 files   6 suites   0s ⏱️
20 tests 14 ✅ 6 💤 0 ❌
57 runs  50 ✅ 7 💤 0 ❌

Results for commit 11ca072.

♻️ This comment has been updated with latest results.