These plots are diagnostic plots for multiple linear regression. The documentation for the `leveragePlot`

function seems straightforward, but I can't get the function to produce anything. Let's do a simple model with `mtcars`

.

```
data(mtcars)
model1=lm(mpg ~ cyl + disp + hp, data=mtcars)
```

From what I can tell, one of the following should produce a plot

```
leveragePlot(model1, cyl)
```

or

```
leveragePlot(model1, ~cyl)
```

but neither does. I consistently get `~cyl is not a term in the model`

and similar errors when I try other terms or combinations of terms. I've also tried explicitly using `terms=`

to no avail.

I imagine this is just my inability to read the help documentation syntax correctly, but I'm at a wall and need some help.