Draws connected dots.

    Parameters
    ----------
    x : array-like, optional
    y : array-like, optional
    label : array-like, optional

    Returns
    -------
    Chart

def _simple_chart(x=None, y=None, name=None, color=None, width=None, dash=None, opacity=None,
                  mode='lines+markers', yaxis=1, fill=None, text='', style='line',
                  markersize=6):
    """Draws connected dots.

    Parameters
    ----------
    x : array-like, optional
    y : array-like, optional
    label : array-like, optional

    Returns
    -------
    Chart

    """
    assert x is not None or y is not None, "x or y must be something"
    if y is None:
        y = x
        x = None
    if x is None:
        x = np.arange(len(y))
    else:
        x = _try_pydatetime(x)
    x = np.atleast_1d(x)
    y = np.atleast_1d(y)
    assert x.shape[0] == y.shape[0]
    xtype = check_type(x[0])
    ytype = check_type(y[0])

    return Chart(dict(
        xAxis=[
            dict(
                type=xtype,
            )
        ],
        yAxis=[
            dict(
                type=ytype,
            )
        ],
        series=[dict(
            type=style,
            name=name,
            data=np.stack((x, y)).T
        )]
    ))