def _draw(x, legend=None, title=None, labels=False,
         show=True, kwargs_list=None, fmt=None, animate=False,
         tail_duration=2, rotations=2, zoom=1, chemtrails=False, precog=False,
         bullettime=False, frame_rate=50, elev=10, azim=-60, duration=30,
         explore=False, size=None, ax=None):
    """
    Draws the plot
    """
    # handle static plots
    def dispatch_static(x, ax=None):
        shape = x[0].shape[1]
        if shape==3:
            opts = dict(projection='3d')
        else:
            opts = dict()
        if not ax:
            fig = plt.figure()
            ax = fig.add_subplot(111, **opts)
        else:
            fig = ax.figure
        if x[0].ndim==1 or x[0].shape[-1]==1:
            return plot1D(x, fig, ax)
        elif x[0].shape[-1]==2:
            return plot2D(x, fig, ax)
        elif x[0].shape[-1]==3:
            return plot3D(x, fig, ax)

    # plot data in 1D
    def plot1D(data, fig, ax):
        n=len(data)
        for i in range(n):
            ikwargs = kwargs_list[i]
            if fmt is None:
                ax.plot(data[i][:,0], **ikwargs)
            else:
                ax.plot(data[i][:,0], fmt[i], **ikwargs)
        return fig, ax, data

    # plot data in 2D
    def plot2D(data, fig, ax):
        n=len(data)
        for i in range(n):
            ikwargs = kwargs_list[i]
            if fmt is None:
                ax.plot(data[i][:,0], data[i][:,1], **ikwargs)
            else:
                ax.plot(data[i][:,0], data[i][:,1], fmt[i], **ikwargs)
        return fig, ax, data

    # plot data in 3D
    def plot3D(data, fig, ax):
        n=len(data)
        for i in range(n):
            ikwargs = kwargs_list[i]
            if fmt is None:
                ax.plot(data[i][:,0], data[i][:,1], data[i][:,2], **ikwargs)
            else:
                ax.plot(data[i][:,0], data[i][:,1], data[i][:,2], fmt[i], **ikwargs)
        return fig, ax, data

    def annotate_plot(data, labels):
        """Create labels in 3d chart
        Args:
            X (np.array) - array of points, of shape (numPoints, 3)
            labels (list) - list of labels of shape (numPoints,1)
        Returns:
            None
        """

        global labels_and_points
        labels_and_points = []

        if data[0].shape[-1]>2:
            proj = ax.get_proj()

        for idx,x in enumerate(data):
            if labels[idx] is not None:
                if data[0].shape[-1]>2:
                    x2, y2, _ = proj3d.proj_transform(x[0], x[1], x[2], proj)
                    label = plt.annotate(
                    labels[idx],
                    xy = (x2, y2), xytext = (-20, 20), textcoords = 'offset points', ha = 'right', va = 'bottom',
                    bbox = dict(boxstyle = 'round,pad=0.5', fc = 'white', alpha = 0.5),
                    arrowprops = dict(arrowstyle = '-', connectionstyle = 'arc3,rad=0'),family='serif')
                    labels_and_points.append((label,x[0],x[1],x[2]))
                elif data[0].shape[-1]==2:
                    x2, y2 = x[0], x[1]
                    label = plt.annotate(
                    labels[idx],
                    xy = (x2, y2), xytext = (-20, 20), textcoords = 'offset points', ha = 'right', va = 'bottom',
                    bbox = dict(boxstyle = 'round,pad=0.5', fc = 'white', alpha = 0.5),
                    arrowprops = dict(arrowstyle = '-', connectionstyle = 'arc3,rad=0'),family='serif')
                    label.draggable()
                    labels_and_points.append((label,x[0],x[1]))
        fig.canvas.draw()

    def update_position(e):
        """Update label positions in 3d chart
        Args:
            e (mouse event) - event handle to update on
        Returns:
            None
        """

        proj = ax.get_proj()
        for label, x, y, z in labels_and_points:
            x2, y2, _ = proj3d.proj_transform(x, y, z, proj)
            label.xy = x2,y2
            label.update_positions(fig.canvas.renderer)
            label._visible=True
        fig.canvas.draw()

    def hide_labels(e):
        """Hides labels on button press
        Args:
            e (mouse event) - event handle to update on
        Returns:
            None
        """

        for label in labels_and_points:
            label[0]._visible=False

    def add_labels(x, labels, explore=False):
        """Add labels to graph if available
        Args:
            data (np.ndarray) - Array containing the data points
            labels (list) - List containing labels
        Returns:
            None
        """
        # if explore mode is activated, implement the on hover behavior
        if explore:
            X = np.vstack(x)
            if labels is not None:
                if any(isinstance(el, list) for el in labels):
                    labels = list(itertools.chain(*labels))
                fig.canvas.mpl_connect('motion_notify_event', lambda event: onMouseMotion(event, X, labels)) # on mouse motion
                # fig.canvas.mpl_connect('button_press_event', lambda event: onMouseClick(event, X, labels))  # on mouse click
            else:
                fig.canvas.mpl_connect('motion_notify_event', lambda event: onMouseMotion(event, X)) # on mouse motion
                # fig.canvas.mpl_connect('button_press_event', lambda event: onMouseClick(event, X, labels))  # on mouse click

        elif labels is not None:
            X = np.vstack(x)
            if any(isinstance(el, list) for el in labels):
                labels = list(itertools.chain(*labels))
            annotate_plot(X, labels)
            fig.canvas.mpl_connect('button_press_event', hide_labels)
            fig.canvas.mpl_connect('button_release_event', update_position)

    ##EXPLORE MODE##
    def distance(point, event):
        """Return distance between mouse position and given data point

        Args:
            point (np.array) -  np.array of shape (3,), with x,y,z in data coords
            event (MouseEvent) - mouse event (which contains mouse position in .x and .xdata)
        Returns:
            distance (np.float64) - distance (in screen coords) between mouse pos and data point
        """
        assert point.shape == (3,), "distance: point.shape is wrong: %s, must be (3,)" % point.shape

        # Project 3d data space to 2d data space
        x2, y2, _ = proj3d.proj_transform(point[0], point[1], point[2], plt.gca().get_proj())
        # Convert 2d data space to 2d screen space
        x3, y3 = ax.transData.transform((x2, y2))

        return np.sqrt ((x3 - event.x)**2 + (y3 - event.y)**2)

    def calcClosestDatapoint(X, event):
        """"Calculate which data point is closest to the mouse position.

        Args:
            X (np.array) - array of points, of shape (numPoints, 3)
            event (MouseEvent) - mouse event (containing mouse position)
        Returns:
            smallestIndex (int) - the index (into the array of points X) of the element closest to the mouse position
        """

        distances = [distance (X[i, 0:3], event) for i in range(X.shape[0])]
        return np.argmin(distances)

    def annotate_plot_explore(X, index, labels=False):
        """Create popover label in 3d chart

        Args:
            X (np.array) - array of points, of shape (numPoints, 3)
            index (int) - index (into points array X) of item which should be printed
            labels (list or False) - list of data point labels (default is False)
        Returns:
            None
        """

        # save clicked points
        if not hasattr(annotate_plot_explore, 'clicked'):
            annotate_plot_explore.clicked = []

        # If we have previously displayed another label, remove it first
        if hasattr(annotate_plot_explore, 'label'):
            if index not in annotate_plot_explore.clicked:
                annotate_plot_explore.label.remove()

        # Get data point from array of points X, at position index
        x2, y2, _ = proj3d.proj_transform(X[index, 0], X[index, 1], X[index, 2], ax.get_proj())

        if type(labels) is list:
            label = labels[index]
        else:
            label = "Index " + str(index) + ": (" + "{0:.2f}, ".format(X[index, 0]) + "{0:.2f}, ".format(X[index, 1]) + "{0:.2f}".format(X[index, 2]) + ")"

        annotate_plot_explore.label = plt.annotate(
        label,
        xy = (x2, y2), xytext = (-20, 20), textcoords = 'offset points', ha = 'right', va = 'bottom',
        bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
        arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))
        fig.canvas.draw()

    def onMouseMotion(event,X,labels=False):
        """Event that is triggered when mouse is moved. Shows text annotation over data point closest to mouse
        Args:
            event (event) - event triggered when the mous is moved
            X (np.ndarray) - coordinates by datapoints matrix
            labels (list or False) - list of data labels (default is False)
        Returns:
            None
        """

        closestIndex = calcClosestDatapoint(X, event)

        if hasattr(onMouseMotion, 'first'):
            pass
        else:
            onMouseMotion.first = False
            onMouseMotion.closestIndex_prev = calcClosestDatapoint(X, event)

        if closestIndex!=onMouseMotion.closestIndex_prev:
            if type(labels) is list:
                annotate_plot_explore (X, closestIndex, labels)
                closestIndex_prev = closestIndex
            else:
                annotate_plot_explore (X, closestIndex)
                closestIndex_prev = closestIndex

    def plot_cube(scale):
        cube = {
            "top"    : ( [[-1,1],[-1,1]], [[-1,-1],[1,1]], [[1,1],[1,1]] ),
            "bottom" : ( [[-1,1],[-1,1]], [[-1,-1],[1,1]], [[-1,-1],[-1,-1]] ),
            "left"   : ( [[-1,-1],[-1,-1]], [[-1,1],[-1,1]], [[-1,-1],[1,1]] ),
            "right"  : ( [[1,1],[1,1]], [[-1,1],[-1,1]], [[-1,-1],[1,1]] ),
            "front"  : ( [[-1,1],[-1,1]], [[-1,-1],[-1,-1]], [[-1,-1],[1,1]] ),
            "back"   : ( [[-1,1],[-1,1]], [[1,1],[1,1]], [[-1,-1],[1,1]] )
            }

        plane_list = []
        for side in cube:
            (Xs, Ys, Zs) = (
                np.asarray(cube[side][0])*scale,
                np.asarray(cube[side][1])*scale,
                np.asarray(cube[side][2])*scale
                )
            plane_list.append(ax.plot_wireframe(Xs, Ys, Zs, rstride=1, cstride=1, color='black', linewidth=1))
        return plane_list

    def plot_square(ax, scale=1):
        ax.add_patch(patches.Rectangle(scale*[-1, -1], scale*2, scale*2, fill=False, edgecolor='black', linewidth=1))

    def update_lines_parallel(num, data_lines, lines, trail_lines, cube_scale, tail_duration=2,
                     rotations=2, zoom=1, chemtrails=False, elev=10):

        if hasattr(update_lines_parallel, 'planes'):
            for plane in update_lines_parallel.planes:
                plane.remove()

        update_lines_parallel.planes = plot_cube(cube_scale)
        ax.view_init(elev=10, azim=rotations*(360*(num/data_lines[0].shape[0])))
        ax.dist=9-zoom

        for line, data, trail in zip(lines, data_lines, trail_lines):

            if (precog and chemtrails) or bullettime:
                trail.set_data(data[:, 0:2].T)
                trail.set_3d_properties(data[:, 2])
            elif chemtrails:
                trail.set_data(data[0:num-tail_duration + 1, 0:2].T)
                trail.set_3d_properties(data[0:num-tail_duration + 1, 2])
            elif precog:
                trail.set_data(data[num+1:, 0:2].T)
                trail.set_3d_properties(data[num+1:, 2])

            if num<=tail_duration:
                    line.set_data(data[0:num+1, 0:2].T)
                    line.set_3d_properties(data[0:num+1, 2])
            else:
                line.set_data(data[num-tail_duration:num+1, 0:2].T)
                line.set_3d_properties(data[num-tail_duration:num+1, 2])

        return lines, trail_lines

    # NOTE: We will include a serial animation version in a future release.  This
    # commented code currently does not work

    # def update_lines_serial(num, data_lines, lines, trail_lines, cube_scale, dataset_idx, plot_idx, tail_duration=2,
    #                  rotations=2, zoom=1, chemtrails=False, elev=10):
    #
    #     if hasattr(update_lines_serial, 'planes'):
    #         for plane in update_lines_serial.planes:
    #             plane.remove()
    #
    #     update_lines_serial.planes = plot_cube(cube_scale)
    #     ax.view_init(elev=10, azim=rotations*(360*(num/data_lines[0].shape[0])))
    #     ax.dist=9-zoom
    #
    #     for idx, (line, data, trail) in enumerate(zip(lines, data_lines, trail_lines)):
    #         if num<=tail_duration and idx is 0:
    #                 line.set_data(data[0:int(plot_idx[num, idx])+1, 0:2].T)
    #                 line.set_3d_properties(data[0:int(plot_idx[num, idx])+1, 2])
    #         elif dataset_idx[num-tail_duration] >= idx:
    #             line.set_data(data[int(plot_idx[num, idx])-tail_duration:int(plot_idx[num, idx])+1, 0:2].T)
    #             line.set_3d_properties(data[int(plot_idx[num, idx])-tail_duration:int(plot_idx[num, idx])+1, 2])
    #             if chemtrails:
    #                 trail.set_data(data[0:int(plot_idx[num, idx]) + 1, 0:2].T)
    #                 trail.set_3d_properties(data[0:int(plot_idx[num, idx]) + 1, 2])
    #         if dataset_idx[num] > idx:
    #             line.set_data(data[num-tail_duration:num+1, 0:2].T)
    #             line.set_3d_properties(data[num-tail_duration:num+1, 2])
    #             if chemtrails:
    #                 trail.set_data(data[0:int(plot_idx[num, idx]) + 1, 0:2].T)
    #                 trail.set_3d_properties(data[0:int(plot_idx[num, idx]) + 1, 2])
    #
    #     return lines, trail_lines

    def update_lines_spin(num, data_lines, lines, cube_scale, rotations=2,
                          zoom=1, elev=10):

        if hasattr(update_lines_spin, 'planes'):
            for plane in update_lines_spin.planes:
                plane.remove()

        update_lines_spin.planes = plot_cube(cube_scale)
        ax.view_init(elev=elev, azim=rotations*(360*(num/(frame_rate*duration))))
        ax.dist=9-zoom

        for line, data in zip(lines, data_lines):
            line.set_data(data[:, 0:2].T)
            line.set_3d_properties(data[:, 2])

        return lines

    def dispatch_animate(x, ani_params):
        if x[0].shape[1] is 3:
            return animate_plot3D(x, **ani_params)

    def animate_plot3D(x, tail_duration=2, rotations=2, zoom=1, chemtrails=False,
                       frame_rate=50, elev=10, style='parallel'):

        # inialize plot
        fig = plt.figure()
        ax = fig.add_subplot(111, projection='3d')

        # create lines
        if fmt is not None:
            lines = [ax.plot(dat[0:1, 0], dat[0:1, 1], dat[0:1, 2], fmt[idx],
                             linewidth=1, **kwargs_list[idx])[0] for idx,dat in enumerate(x)]
            if is_line(fmt):
                trail = [ax.plot(dat[0:1, 0], dat[0:1, 1], dat[0:1, 2], fmt[idx],
                                 alpha=.3, linewidth=1, **kwargs_list[idx])[0] for idx, dat in enumerate(x)]
        else:
            lines = [ax.plot(dat[0:1, 0], dat[0:1, 1], dat[0:1, 2],
                             linewidth=1, **kwargs_list[idx])[0] for idx,dat in enumerate(x)]
            if is_line(fmt):
                trail = [ax.plot(dat[0:1, 0], dat[0:1, 1], dat[0:1, 2],
                                 alpha=.3, linewidth=1, **kwargs_list[idx])[0] for idx, dat in enumerate(x)]
        if tail_duration==0:
            tail_duration=1
        else:
            tail_duration = int(frame_rate*tail_duration)

        # get line animation
        if style in ['parallel', True]:
            line_ani = animation.FuncAnimation(fig, update_lines_parallel, x[0].shape[0],
                            fargs=(x, lines, trail, 1, tail_duration, rotations, zoom, chemtrails, elev),
                            interval=1000/frame_rate, blit=False, repeat=False)
        # elif style == 'serial':
        #     dataset_idx = []
        #     for idx, data in enumerate(x):
        #         for i in range(data.shape[0]):
        #             dataset_idx.append(idx)
        #     plot_idx = np.empty((np.sum([data.shape[0] for data in x]), len(x))) * 0
        #     start=int(0)
        #     end=int(x[0].shape[0])
        #     for idx, d in enumerate(x):
        #         plot_idx[start:end,idx] = [int(i) for i in range(d.shape[0])]
        #         plot_idx[end:,idx]=int(d.shape[0])
        #         if idx+1 < len(x):
        #             start+=int(d.shape[0])-tail_duration
        #             end+=int(x[idx+1].shape[0])-tail_duration
        #     line_ani = animation.FuncAnimation(fig, update_lines_serial, np.sum([i.shape[0] for i in x]),
        #                     fargs=(x, lines, trail, 1, dataset_idx, plot_idx,
        #                     tail_duration, rotations, zoom, chemtrails, elev),
        #                     interval=1000/frame_rate, blit=False, repeat=False)
        elif style == 'spin':
            line_ani = animation.FuncAnimation(fig, update_lines_spin, frame_rate*duration,
                            fargs=(x, lines, 1, rotations, zoom, elev),
                            interval=1000/frame_rate, blit=False, repeat=False)

        return fig, ax, x, line_ani

    # if a single point, but formatted as a line, replace with a point
    for i, (xi, fi) in enumerate(zip(x, fmt)):
        if xi.shape[0]==1 and fi in ('-', ':', '--'):
            fmt[i]='.'

    if not show:
        # prevents the backend from rendering this plot
        plt.ioff()

    if animate in [True, 'parallel', 'spin']:
        assert x[0].shape[1] is 3, "Animations are currently only supported for 3d plots."

        # animation params
        ani_params = dict(tail_duration=tail_duration,
                          rotations=rotations,
                          zoom=zoom,
                          chemtrails=chemtrails,
                          frame_rate=frame_rate,
                          elev=elev,
                          style=animate)

        # dispatch animation
        fig, ax, data, line_ani = dispatch_animate(x, ani_params)

    else:

        # dispatch static
        fig, ax, data = dispatch_static(x, ax)

        # if 3d, plot the cube
        if x[0].shape[1] is 3:

            # set cube scale
            cube_scale = 1

            # plot cube
            plot_cube(cube_scale)

            # set the axes properties
            ax.set_xlim3d([-cube_scale, cube_scale])
            ax.set_ylim3d([-cube_scale, cube_scale])
            ax.set_zlim3d([-cube_scale, cube_scale])

            # initialize the view
            ax.view_init(elev=elev, azim=azim)

        elif x[0].shape[1] is 2:

            # plot square
            plot_square(ax)

            # set axes
            ax.set_xlim(-1.1, 1.1)
            ax.set_ylim(-1.1, 1.1)

        # set line_ani to empty
        line_ani = None

    # remove axes
    ax.set_axis_off()

    # add labels
    add_labels(x, labels, explore=explore)

    # add title
    if title is not None:
        ax.set_title(title)

    # add legend
    if legend is not None:
        ax.legend()

    if size is not None:
        fig.set_size_inches(size)

    return fig, ax, data, line_ani
Draws the plot