Merge pull request #6231 from m-ad/owcsvimport_deprection

Fix deprecation warning for read_csv prefix argument (#6220)

Author: markotoplak

Orange/widgets/data/owcsvimport.py

@@ -1554,11 +1554,14 @@ def expand(ranges):
             file, sep=opts.dialect.delimiter, dialect=opts.dialect,
             skipinitialspace=opts.dialect.skipinitialspace,
             header=header, skiprows=skiprows,
-            dtype=dtypes, parse_dates=parse_dates, prefix=prefix,
+            dtype=dtypes, parse_dates=parse_dates,
             na_values=na_values, keep_default_na=False,
             **numbers_format_kwds
         )
 
+        if prefix:
+            df.columns = [f"{prefix}{column}" for column in df.columns]
+
         # for older workflows avoid guessing type guessing
         if not compatibility_mode:
             df = guess_types(df, dtypes, columns_ignored)