# Buggy code
def drop(
    self,
    labels=None,
    axis=0,
    index=None,
    columns=None,
    level=None,
    inplace=False,
    errors="raise",
):
    """
    Return new object with labels in requested axis removed.

    Parameters
    ----------
    labels : single label or list-like
        Index or column labels to drop.
    axis : int or axis name
        Whether to drop labels from the index (0 / 'index') or
        columns (1 / 'columns').
    index, columns : single label or list-like
        Alternative to specifying `axis` (``labels, axis=1`` is
        equivalent to ``columns=labels``).

        .. versionadded:: 0.21.0
    level : int or level name, default None
        For MultiIndex
    inplace : bool, default False
        If True, do operation inplace and return None.
    errors : {'ignore', 'raise'}, default 'raise'
        If 'ignore', suppress error and existing labels are dropped.

    Returns
    -------
    dropped : type of caller

    Examples
    --------
    >>> df = pd.DataFrame(np.arange(12).reshape(3,4),
                          columns=['A', 'B', 'C', 'D'])
    >>> df
       A  B   C   D
    0  0  1   2   3
    1  4  5   6   7
    2  8  9  10  11

    Drop columns

    >>> df.drop(['B', 'C'], axis=1)
       A   D
    0  0   3
    1  4   7
    2  8  11

    >>> df.drop(columns=['B', 'C'])
       A   D
    0  0   3
    1  4   7
    2  8  11

    Drop a row by index

    >>> df.drop([0, 1])
       A  B   C   D
    2  8  9  10  11

    Notes
    -----
    Specifying both `labels` and `index` or `columns` will raise a
    ValueError.

    """
    inplace = validate_bool_kwarg(inplace, "inplace")

    if labels is not None:
        if index is not None or columns is not None:
            raise ValueError("Cannot specify both 'labels' and 'index'/'columns'")
        axis_name = self._get_axis_name(axis)
        axes = {axis_name: labels}
    elif index is not None or columns is not None:
        axes, _ = self._construct_axes_from_arguments((index, columns), {})
    else:
        raise ValueError(
            "Need to specify at least one of 'labels', 'index' or 'columns'"
        )

    obj = self

    for axis, labels in axes.items():
        if labels is not None:
            obj = obj._drop_axis(labels, axis, level=level, errors=errors)

    if inplace:
        self._update_inplace(obj)
    else:
        return obj


# Traceback (ValueError)
items.drop('abcd',axis=1)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.6/site-packages/pandas/core/generic.py", line 2530, in drop
obj = obj._drop_axis(labels, axis, level=level, errors=errors)
File "/usr/local/lib/python3.6/site-packages/pandas/core/generic.py", line 2562, in _drop_axis
new_axis = axis.drop(labels, errors=errors)
File "/usr/local/lib/python3.6/site-packages/pandas/core/indexes/base.py", line 3744, in drop
labels[mask])
ValueError: labels ['abcd'] not contained in axis

# Fixed code
def drop(
    self,
    labels=None,
    axis=0,
    index=None,
    columns=None,
    level=None,
    inplace=False,
    errors="raise",
):
    """
    Return new object with labels in requested axis removed.

    Parameters
    ----------
    labels : single label or list-like
        Index or column labels to drop.
    axis : int or axis name
        Whether to drop labels from the index (0 / 'index') or
        columns (1 / 'columns').
    index, columns : single label or list-like
        Alternative to specifying `axis` (``labels, axis=1`` is
        equivalent to ``columns=labels``).

        .. versionadded:: 0.21.0
    level : int or level name, default None
        For MultiIndex
    inplace : bool, default False
        If True, do operation inplace and return None.
    errors : {'ignore', 'raise'}, default 'raise'
        If 'ignore', suppress error and existing labels are dropped.

    Returns
    -------
    dropped : type of caller

    Raises
    ------
    KeyError
        If none of the labels are found in the selected axis

    Examples
    --------
    >>> df = pd.DataFrame(np.arange(12).reshape(3,4),
                          columns=['A', 'B', 'C', 'D'])
    >>> df
       A  B   C   D
    0  0  1   2   3
    1  4  5   6   7
    2  8  9  10  11

    Drop columns

    >>> df.drop(['B', 'C'], axis=1)
       A   D
    0  0   3
    1  4   7
    2  8  11

    >>> df.drop(columns=['B', 'C'])
       A   D
    0  0   3
    1  4   7
    2  8  11

    Drop a row by index

    >>> df.drop([0, 1])
       A  B   C   D
    2  8  9  10  11

    Notes
    -----
    Specifying both `labels` and `index` or `columns` will raise a
    ValueError.

    """
    inplace = validate_bool_kwarg(inplace, "inplace")

    if labels is not None:
        if index is not None or columns is not None:
            raise ValueError("Cannot specify both 'labels' and 'index'/'columns'")
        axis_name = self._get_axis_name(axis)
        axes = {axis_name: labels}
    elif index is not None or columns is not None:
        axes, _ = self._construct_axes_from_arguments((index, columns), {})
    else:
        raise ValueError(
            "Need to specify at least one of 'labels', 'index' or 'columns'"
        )

    obj = self

    for axis, labels in axes.items():
        if labels is not None:
            obj = obj._drop_axis(labels, axis, level=level, errors=errors)

    if inplace:
        self._update_inplace(obj)
    else:
        return obj