# Buggy code
def _getitem_slice(self, key):
    # If there is no step, we can fasttrack the codepath to use existing logic from
    # head and tail, which is already pretty fast.
    if (
        key.step is None
        and (isinstance(key.start, int) or key.start is None)
        and (isinstance(key.stop, int) or key.stop is None)
    ):
        if key.start is None and key.stop is None:
            return self.copy()

        def compute_offset(value):
            return (
                value - len(self) if value > 0 else value if value != 0 else len(self)
            )

        # Head is a negative number, Tail is a positive number
        if key.start is None:
            return self.head(compute_offset(key.stop))
        elif key.stop is None:
            return self.tail(compute_offset(-key.start))
        return self.head(compute_offset(key.stop)).tail(compute_offset(-key.start))
    # We convert to a RangeIndex because getitem_row_array is expecting a list
    # of indices, and RangeIndex will give us the exact indices of each boolean
    # requested.
    if isinstance(key.start, int) and isinstance(key.stop, int):
        key = pandas.RangeIndex(len(self.index))[key]
    else:
        # To handle this case correctly, we let pandas compute the indices by
        # creating a MultiIndex ("a", "b") such that "a" is the original index and
        # "b" is the Range of numeric indices for each. Then we apply the slice to
        # the original index (named "a"), then extract the index values (named "b")
        # and pass that along to be sliced in the actual data. This also serves as a
        # validation that the input slice is usable and correct.
        key = pandas.DataFrame(
            index=pandas.MultiIndex.from_arrays(
                [self.index, pandas.RangeIndex(len(self.index))], names=["a", "b"]
            )
        )[key].index.get_level_values("b")
    return self.__constructor__(
        query_compiler=self._query_compiler.getitem_row_array(key)
    )


# Traceback (Exception)
---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-6-525f4cb2bfb2> in <module>
----> 1 c[3:7]

~/software_builds/modin/modin/pandas/base.py in __getitem__(self, key)
3254         )
3255         if indexer is not None:
-> 3256             return self._getitem_slice(indexer)
3257         else:
3258             return self._getitem(key)

~/software_builds/modin/modin/pandas/base.py in _getitem_slice(self, key)
3283             elif key.stop is None:
3284                 return self.tail(compute_offset(-key.start))
-> 3285             return self.head(compute_offset(key.stop)).tail(compute_offset(-key.start))
3286         # We convert to a RangeIndex because getitem_row_array is expecting a list
3287         # of indices, and RangeIndex will give us the exact indices of each boolean

~/software_builds/modin/modin/pandas/series.py in tail(self, n)
1052         if n == 0:
1053             return Series(dtype=self.dtype)
-> 1054         return super(Series, self).tail(n)
1055
1056     def take(self, indices, axis=0, is_copy=None, **kwargs):

~/software_builds/modin/modin/pandas/base.py in tail(self, n)
2789         if n >= len(self.index):
2790             return self.copy()
-> 2791         return self.__constructor__(query_compiler=self._query_compiler.tail(n))
2792
2793     def to_clipboard(self, excel=True, sep=None, **kwargs):  # pragma: no cover

~/software_builds/modin/modin/backends/pandas/query_compiler.py in tail(self, n)
808             QueryCompiler containing the last n rows of the original QueryCompiler.
809         """
--> 810         return self.__constructor__(self._modin_frame.tail(n))
811
812     def front(self, n):

~/software_builds/modin/modin/engines/base/frame/data.py in tail(self, n)
1355             new_row_lengths,
1356             self._column_widths,
-> 1357             self._dtypes,
1358         )
1359

~/software_builds/modin/modin/engines/base/frame/data.py in __init__(self, partitions, index, columns, row_lengths, column_widths, dtypes)
62                 sum(row_lengths) != len(self._index_cache),
63                 "Row lengths: {} != {}".format(
---> 64                     sum(row_lengths), len(self._index_cache)
65                 ),
66             )

~/software_builds/modin/modin/error_message.py in catch_bugs_and_request_email(cls, failure_condition, extra_log)
51                 "Internal Error. "
52                 "Please email bug_reports@modin.org with the traceback and command that"
---> 53                 " caused this error.\n{}".format(extra_log)
54             )
55

Exception: Internal Error. Please email bug_reports@modin.org with the traceback and command that caused this error.
Row lengths: 0 != 2

# Fixed code
def _getitem_slice(self, key):
    if key.start is None and key.stop is None:
        return self.copy()
    return self.iloc[key]