# Buggy code
def _map(df, other):
    # Set `as_index` to True to track the metadata of the grouping object
    # It is used to make sure that between phases we are constructing the
    # right index and placing columns in the correct order.
    groupby_args["as_index"] = True
    other = other.squeeze(axis=axis ^ 1)
    if isinstance(other, pandas.DataFrame):
        df = pandas.concat([df] + [other[[o for o in other if o not in df]]], axis=1)
        other = list(other.columns)
    result = map_func(df.groupby(by=other, axis=axis, **groupby_args), **map_args)
    if (
        not isinstance(result.index, pandas.MultiIndex)
        and result.index.name is not None
        and result.index.name in result.columns
    ):
        result.index.name = "{}{}".format("_modin_groupby_", result.index.name)
    return result.reset_index(drop=False)


# Traceback (ValueError)
Traceback (most recent call last):
File "/localdisk/gashiman/omniscripts/taxi/taxibench_pandas.py", line 190, in <module>
query(query_df)
File "/localdisk/gashiman/omniscripts/taxi/taxibench_pandas.py", line 95, in q3
return transformed.groupby(['passenger_count','pickup_datetime'])[['passenger_count','pickup_datetime']].count()['passenger_count']
File "/nfs/site/proj/scripting_tools/gashiman/modin/modin/pandas/groupby.py", line 249, in __getitem__
return SeriesGroupBy(self._default_to_pandas(lambda df: df.__getitem__(key)))
File "/nfs/site/proj/scripting_tools/gashiman/modin/modin/pandas/groupby.py", line 535, in _default_to_pandas
return self._df._default_to_pandas(groupby_on_multiple_columns)
File "/nfs/site/proj/scripting_tools/gashiman/modin/modin/pandas/base.py", line 227, in _default_to_pandas
result = op(pandas_obj, *args, **kwargs)
File "/nfs/site/proj/scripting_tools/gashiman/modin/modin/pandas/groupby.py", line 533, in groupby_on_multiple_columns
return f(df.groupby(by=by, axis=self._axis, **self._kwargs), **kwargs)
File "/nfs/site/home/gashiman/.local/lib/python3.7/site-packages/pandas/core/generic.py", line 7894, in groupby
**kwargs
File "/nfs/site/home/gashiman/.local/lib/python3.7/site-packages/pandas/core/groupby/groupby.py", line 2522, in groupby
return klass(obj, by, **kwds)
File "/nfs/site/home/gashiman/.local/lib/python3.7/site-packages/pandas/core/groupby/groupby.py", line 391, in __init__
mutated=self.mutated,
File "/nfs/site/home/gashiman/.local/lib/python3.7/site-packages/pandas/core/groupby/grouper.py", line 652, in _get_grouper
if not isinstance(gpr, Grouping)
File "/nfs/site/home/gashiman/.local/lib/python3.7/site-packages/pandas/core/groupby/grouper.py", line 347, in __init__
raise ValueError("Grouper for '{}' not 1-dimensional".format(t))
ValueError: Grouper for '<class 'pandas.core.frame.DataFrame'>' not 1-dimensional

# Fixed code
def _map(df, other):
    # Set `as_index` to True to track the metadata of the grouping object
    # It is used to make sure that between phases we are constructing the
    # right index and placing columns in the correct order.
    groupby_args["as_index"] = True
    other = other.squeeze(axis=axis ^ 1)
    if isinstance(other, pandas.DataFrame):
        df = pandas.concat([df] + [other[[o for o in other if o not in df]]], axis=1)
        other = list(other.columns)
    result = map_func(df.groupby(by=other, axis=axis, **groupby_args), **map_args)
    if (
        not isinstance(result.index, pandas.MultiIndex)
        and result.index.name is not None
        and result.index.name in result.columns
    ):
        result.index.name = "{}{}".format("_modin_groupby_", result.index.name)
    return result