lme can't find functions to set correlation / covariance structure and weights

I’m currently trying to model a multivariate mixed model.

Im trying to include weights and a covariance structure like so:

model <- nlme::lme(fixed = ..., data = ...., random = ..., weights = varIdent(form = ~ 1 | Gender))

or

model <- nlme::lme(fixed = ..., data = ...., random = ..., corr = corAR1())

I also tried using correlation instead of corr.

However, I get error-messages:

Error in corAR1() : could not find function "corAR1"

Error in varIdent(form = ~1 | Gender) : could not find function "varIdent"

I have tried deleting the Global enviroment and loading everything fresh.
I also reinstalled nlme and typed getAnywhere(corAR1) and getAnywhere(varIdent) as suggested in this post.

Do you have any ideas?
Many thanks!

>Solution :

Do you call library(nlme) before running? And did you try including nlme::corAR1()/nlme::varIdent() inside the call itself ?