it seems a bug of trainModel.R

https://github.com/powellgenomicslab/scPred/blob/86e62305544cfd933562a707b3cea60a997978d0/R/trainModel.R#L53

```
if(!is(object, "Seurat") | is(object, "scPred")){
```
should be

```
if(!(is(object, "Seurat") | is(object, "scPred"))){
```