'Adds one top-level :class:`Parameter <pyqtgraph.parametertree.Parameter>`
to the view.
**Arguments:**
param          The :class:`Parameter <pyqtgraph.parametertree.Parameter>`
to add.
root           The item within the tree to which *param* should be added.
By default, *param* is added as a top-level item.
showTop        If False, then *param* will be hidden, and only its
children will be visible in the tree.'

def addParameters(self, param, root=None, depth=0, showTop=True):

    item = param.makeTreeItem(depth=depth)
    if (root is None):
        root = self.invisibleRootItem()
        if (not showTop):
            item.setText(0, '')
            item.setSizeHint(0, QtCore.QSize(1, 1))
            item.setSizeHint(1, QtCore.QSize(1, 1))
            depth -= 1
    root.addChild(item)
    item.treeWidgetChanged()
    for ch in param:
        self.addParameters(ch, root=item, depth=(depth + 1))
