Error messages in "Explorando data frames"

[Zulemma]

In "Explorando Data Frames" episode when we run

gatos <- rbind(gatos, nueva_fila)

there is no an error message about "invalid factor level". May add a little a chunk of code and show the error message obtained to become clear.

[nselem]

Dear Zulema
Thank you for pointing this out; the problem is that the color column was not a factor. I have added a chunk to convert it into a factor column, and now the error should be visible. Since these episodes are in r-markdown the output chunks are automatically generated. But now the following error should be shown:
Warning message:
In [<-.factor(*tmp*, ri, value = "carey") :
invalid factor level, NA generated