I get an error when I try to run `glm.mids` on a subset of a `mids` imputation object:

```
library(mice)
imp2 = mice(nhanes)
glm.mids( (hyp==2)~bmi+chl, data=imp2, subset=(age==1) )

```

gives the cryptic error message

```
"Error in eval(expr, envir, enclos) :
..1 used in an incorrect context, no ... to look in"

```

even though the syntax works with regular `glm` on the original dataset:

```
glm( (hyp==2)~bmi+chl, data=nhanes, subset=(age==1) )

```

The documentation `?glm.mids` doesn't specifically address `subset` but says that you can pass additional parameters onto `glm`. If I can't use `subset` with `glm.mids`, is there a good way to subset the `mids` list object directly?