Merge branch 'fix_standardize_trim_table_argument' into 'development'

Fix standardize trim_table argument

See merge request !253

docs/source/versions/changelog.rst

 Change log
 ==========
 
+**Version 2.6.2** (Month Day, Year)
+
+ * Fixed bug in :meth:`standardize <ketos.data_handling.selection_table.standardize>` where setting `trim_table=True` and `mapper=None` would give an error.
+
 **Version 2.6.1** (June 3, 2022)
 
  * In :meth:`AudioWriter:close <ketos.data_handling.database_interface.AudioWriter.close>` remove any existing column indices before attempting to reindex them. (Only relevant if appending to an existing database.)

ketos/data_handling/selection_table.py

@@ -267,8 +267,11 @@ def standardize(table=None, path=None, sep=',', mapper=None, labels=None,
 
     # keep only relevant columns
     if trim_table:
-        df = trim(df, list(mapper.keys()))
-
+        if mapper is not None:
+            df = trim(df, list(mapper.keys()))
+        else:
+            df = trim(df)
+            
     # check that dataframe has minimum required columns
     mis = missing_columns(df)
     assert len(mis) == 0, 'Column(s) {0} missing from input table'.format(mis)