'Plot the autocorrelation of `x`.
Parameters
x : sequence of scalar
hold : boolean, optional, *deprecated*, default: True
detrend : callable, optional, default: `mlab.detrend_none`
x is detrended by the `detrend` callable. Default is no
normalization.
normed : boolean, optional, default: True
if True, input vectors are normalised to unit length.
usevlines : boolean, optional, default: True
if True, Axes.vlines is used to plot the vertical lines from the
origin to the acorr. Otherwise, Axes.plot is used.
maxlags : integer, optional, default: 10
number of lags to show. If None, will return all 2 * len(x) - 1
lags.
Returns
(lags, c, line, b) : where:
- `lags` are a length 2`maxlags+1 lag vector.
- `c` is the 2`maxlags+1 auto correlation vectorI
- `line` is a `~matplotlib.lines.Line2D` instance returned by
`plot`.
- `b` is the x-axis.
Other Parameters
linestyle : `~matplotlib.lines.Line2D` prop, optional, default: None
Only used if usevlines is False.
marker : string, optional, default: \'o\'
Notes
The cross correlation is performed with :func:`numpy.correlate` with
`mode` = 2.'

@_preprocess_data(replace_names=[u'x'], label_namer=u'x')
def acorr(self, x, **kwargs):

    if (u'hold' in kwargs):
        warnings.warn(u"the    'hold'    kwarg    is    deprecated", mplDeprecation)
    return self.xcorr(x, x, **kwargs)
