fcm function doesn't work with corpus object in 0.9.9-3

`fcm()` works on a text object, but not on a corpus.  When I try to apply to a corpus object created with quanteda I get the following error: 

`Error in UseMethod("fcm") : 
  no applicable method for 'fcm' applied to an object of class "c('corpus', 'list')"`
```
txts <- c("a a a b b c", "a a c e", "a c e f g")
myCorpus <- corpus(txts)
fcm(myCorpus, context = "document")
```