Retrieve all the entries of disease.drug table

Hello, 

Is there a way to retrieve all the entries in the 'disease.drug' table without indicating a specific drug or disease? For instance, something like: 

```
all_drugs <- get_multimir(disease.drug='all.drugs', table='disease.drug') 
all_disease <- get_multimir(disease.drug='all.diseases', table='disease.drug') 
```

And get all the drugs and diseases of the table. 

Thanks! 
