Extract common pattern in comparison stat functions to reduce CCN

[Copilot]

• Create a generic helper function _apply_comparison_stat_to_BalanceDF to reduce code duplication
• Update _asmd_BalanceDF to use the new helper function
• Update _kld_BalanceDF to use the new helper function
• Update _emd_BalanceDF to use the new helper function
• Update _cvmd_BalanceDF to use the new helper function
• Update _ks_BalanceDF to use the new helper function
• Run tests to ensure all functionality remains unchanged (all 83 tests in test_balancedf.py pass)
• Run code review and security checks (no issues found)
• Add direct test coverage for _kld_BalanceDF, _emd_BalanceDF, _cvmd_BalanceDF, and _ks_BalanceDF (5 new tests added)
• Fix flake8 linting errors (removed trailing whitespace from blank lines)
• Fix ufmt formatting errors (formatted test file with ufmt)

Summary

Successfully extracted the common pattern from five similar functions (_asmd_BalanceDF, _kld_BalanceDF, _emd_BalanceDF, _cvmd_BalanceDF, _ks_BalanceDF) into a single generic helper function _apply_comparison_stat_to_BalanceDF.

Changes Made

• Added Callable to the imports from typing module
• Created _apply_comparison_stat_to_BalanceDF helper function that:
  1. Validates inputs are BalanceDF objects
  2. Extracts df and weights from both objects
  3. Calls the comparison function with the extracted data
• Refactored all five comparison functions to use the helper (reduced from ~30 lines to ~5 lines each)
• Maintains special handling for _asmd_BalanceDF which passes std_type="target" via kwargs
• Added comprehensive test coverage for all comparison methods:
  • test_BalanceDF__kld_BalanceDF: Direct test of _kld_BalanceDF method
  • test_BalanceDF__emd_BalanceDF: Direct test of _emd_BalanceDF method
  • test_BalanceDF__cvmd_BalanceDF: Direct test of _cvmd_BalanceDF method
  • test_BalanceDF__ks_BalanceDF: Direct test of _ks_BalanceDF method
  • test_BalanceDF_comparison_functions_invalid_input: Tests input validation for all methods
• Fixed flake8 linting errors: Removed trailing whitespace from blank lines in test file
• Fixed ufmt formatting: Formatted test file according to project standards (black + usort)

Test Coverage

• All tests now directly exercise the helper function through the four comparison methods
• Tests verify correct Series output with expected keys (a, b, mean(metric))
• Tests verify mathematical properties (non-negativity, bounded ranges)
• Tests verify aggregate_by_main_covar parameter works
• Tests verify proper input validation with clear error messages
• Total tests: 88 (83 original + 5 new), all passing
• Code quality compliance: All linting (flake8) and formatting (ufmt) checks pass

Benefits

• Reduces Cyclomatic Complexity Number (CCN) - the original goal of the issue
• Eliminates code duplication - DRY principle applied
• Easier maintenance - future changes only need to be made in one place
• Type safety - added proper type hint for the callable parameter
• No behavioral changes - all 83 existing tests pass without modification
• Comprehensive test coverage - direct tests for all comparison methods and edge cases
• Code quality - passes all linting and formatting checks

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[FEATURE] generalize functions in ‎balance/balancedf_class.py‎</issue_title>
<issue_description>a bunch of functions in
‎balance/balancedf_class.py‎

Follow the exact same pattern (other than one word change:
@staticmethod
def _emd_BalanceDF(
sample_BalanceDF: "BalanceDF",
target_BalanceDF: "BalanceDF",
aggregate_by_main_covar: bool = False,
) -> pd.Series:
"""Run EMD on two BalanceDF objects.

    Prepares the BalanceDF objects by passing them through :func:`_get_df_and_weights`, and
    then passes the df and weights into :func:`weighted_comparisons_stats.emd`.

    Args:
        sample_BalanceDF (BalanceDF): Object.
        target_BalanceDF (BalanceDF): Object.
        aggregate_by_main_covar (bool, optional): See :func:`weighted_comparisons_stats.emd`. Defaults to False.

    Returns:
        pd.Series: See :func:`weighted_comparisons_stats.emd`.
    """
    BalanceDF._check_if_not_BalanceDF(sample_BalanceDF, "sample_BalanceDF")
    BalanceDF._check_if_not_BalanceDF(target_BalanceDF, "target_BalanceDF")

    sample_df_values, sample_weights = sample_BalanceDF._get_df_and_weights()
    target_df_values, target_weights = target_BalanceDF._get_df_and_weights()

    return weighted_comparisons_stats.emd(
        sample_df_values,
        target_df_values,
        sample_weights,
        target_weights,
        aggregate_by_main_covar=aggregate_by_main_covar,
    )

Extract this pattern to a helper function to reduce CCN.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [FEATURE] generalize functions in ‎balance/balancedf_class.py‎ #266

---

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[Copilot]

Pull request overview

This PR refactors five comparison statistic methods (_asmd_BalanceDF, _kld_BalanceDF, _emd_BalanceDF, _cvmd_BalanceDF, _ks_BalanceDF) in the BalanceDF class to reduce code duplication and cyclomatic complexity by extracting a common pattern into a new helper method _apply_comparison_stat_to_BalanceDF.

Changes:

• Introduced _apply_comparison_stat_to_BalanceDF helper that centralizes validation, data extraction, and delegation to comparison functions
• Refactored five static methods to use the helper, reducing each from ~15 lines to ~5 lines
• Added Callable to the typing imports for proper type hinting

[talgalili]

@copilot apply changes based on the comments in this thread

[talgalili]

@copilot

Fix

Run flake8 .
flake8 .
shell: /usr/bin/bash -e {0}
env:
pythonLocation: /opt/hostedtoolcache/Python/3.12.12/x64
PKG_CONFIG_PATH: /opt/hostedtoolcache/Python/3.12.12/x64/lib/pkgconfig
Python_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
Python2_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
Python3_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.12.12/x64/lib
./tests/test_balancedf.py:1311:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1317:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1319:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1325:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1328:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1340:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1346:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1348:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1354:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1357:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1369:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1375:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1377:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1383:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1386:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1398:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1404:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1406:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1412:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1416:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1428:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1431:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1434:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1437:1: W293 blank line contains whitespace
./tests/test_balancedf.py:1440:1: W293 blank line contains whitespace
Error: Process completed with exit code 1.

[Copilot]

@copilot

Fix
...

Fixed flake8 errors by removing trailing whitespace from blank lines in commit cbb7a17. All 25 W293 warnings have been resolved.

[talgalili]

@copilot fix

Run ufmt check .
ufmt check .
shell: /usr/bin/bash -e {0}
env:
pythonLocation: /opt/hostedtoolcache/Python/3.12.12/x64
PKG_CONFIG_PATH: /opt/hostedtoolcache/Python/3.12.12/x64/lib/pkgconfig
Python_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
Python2_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
Python3_ROOT_DIR: /opt/hostedtoolcache/Python/3.12.12/x64
LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.12.12/x64/lib
Would format /home/runner/work/balance/balance/tests/test_balancedf.py
✨ 1 file would be formatted, 53 files already formatted ✨
Error: Process completed with exit code 1.

[Copilot]

@copilot fix

Run ufmt check .
...

Fixed ufmt formatting errors by running ufmt format on the test file in commit 6b32a40. The file is now properly formatted according to the project's black + usort standards.

[meta-codesync]

@talgalili has imported this pull request. If you are a Meta employee, you can view this in D90870323.

[meta-codesync]

@talgalili merged this pull request in c7fcb79.