# Buggy code
def _make_plot(self):
    colors = "brgyk"
    rects = []
    labels = []

    ax = self.axes[0]

    bar_f = self.bar_f

    pos_prior = neg_prior = np.zeros(len(self.data))

    K = self.nseries

    for i, (label, y) in enumerate(self._iter_data()):
        kwds = self.kwds.copy()
        if "color" not in kwds:
            kwds["color"] = colors[i % len(colors)]

        if self.subplots:
            ax = self.axes[i]
            rect = bar_f(ax, self.ax_pos, y, 0.5, start=pos_prior, linewidth=1, **kwds)
            ax.set_title(label)
        elif self.stacked:
            mask = y > 0
            start = np.where(mask, pos_prior, neg_prior)

            rect = bar_f(
                ax, self.ax_pos, y, 0.5, start=start, label=label, linewidth=1, **kwds
            )
            pos_prior = pos_prior + np.where(mask, y, 0)
            neg_prior = neg_prior + np.where(mask, 0, y)
        else:
            rect = bar_f(
                ax,
                self.ax_pos + i * 0.75 / K,
                y,
                0.75 / K,
                start=pos_prior,
                label=label,
                **kwds,
            )
        rects.append(rect)
        labels.append(label)

    if self.legend and not self.subplots:
        patches = [r[0] for r in rects]

        # Legend to the right of the plot
        # ax.legend(patches, labels, bbox_to_anchor=(1.05, 1),
        #           loc=2, borderaxespad=0.)
        # self.fig.subplots_adjust(right=0.80)

        ax.legend(patches, labels, loc="best")

    self.fig.subplots_adjust(top=0.8)


# Traceback (ValueError)
In [17]: date_range(datetime.datetime.today(), periods=10, freq='2h20m')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/home/chang/Dropbox/git/pandas/<ipython-input-17-ff4e03382573> in <module>()
----> 1 date_range(datetime.datetime.today(), periods=10, freq='2h20m')

/home/chang/Dropbox/git/pandas/pandas/tseries/index.pyc in date_range(start, end, periods, freq, tz, normalize)
1209     """
1210     return DatetimeIndex(start=start, end=end, periods=periods,
-> 1211                          freq=freq, tz=tz, normalize=normalize)
1212
1213

/home/chang/Dropbox/git/pandas/pandas/tseries/index.pyc in __new__(cls, data, freq, start, end, periods, copy, name, tz, verify_integrity, normalize, **kwds)
202
203         if data is None and offset is None:
--> 204             raise ValueError("Must provide freq argument if no data is "
205                              "supplied")
206

ValueError: Must provide freq argument if no data is supplied

# Fixed code
def _make_plot(self):
    colors = "brgyk"
    rects = []
    labels = []

    ax = self.axes[0]

    bar_f = self.bar_f

    pos_prior = neg_prior = np.zeros(len(self.data))

    K = self.nseries

    for i, (label, y) in enumerate(self._iter_data()):
        kwds = self.kwds.copy()
        if "color" not in kwds:
            kwds["color"] = colors[i % len(colors)]

        if self.subplots:
            ax = self.axes[i]
            rect = bar_f(ax, self.ax_pos, y, 0.5, start=pos_prior, linewidth=1, **kwds)
            ax.set_title(label)
        elif self.stacked:
            mask = y > 0
            start = np.where(mask, pos_prior, neg_prior)

            rect = bar_f(
                ax, self.ax_pos, y, 0.5, start=start, label=label, linewidth=1, **kwds
            )
            pos_prior = pos_prior + np.where(mask, y, 0)
            neg_prior = neg_prior + np.where(mask, 0, y)
        else:
            rect = bar_f(
                ax,
                self.ax_pos + i * 0.75 / K,
                y,
                0.75 / K,
                start=pos_prior,
                label=label,
                **kwds,
            )
        rects.append(rect)
        labels.append(label)

    if self.legend and not self.subplots:
        patches = [r[0] for r in rects]

        # Legend to the right of the plot
        # ax.legend(patches, labels, bbox_to_anchor=(1.05, 1),
        #           loc=2, borderaxespad=0.)
        # self.fig.subplots_adjust(right=0.80)

        ax.legend(patches, labels, loc="best", title=self.legend_title)

    self.fig.subplots_adjust(top=0.8, wspace=0, hspace=0)