How to use the data in gwascatelog directly?

[yanhuayizha]

I use the following codes (which learned from https://mrcieu.github.io/TwoSampleMR/articles/exposure.html)
remotes::install_github("MRCIEU/MRInstruments")
library(MRInstruments)
library(TwoSampleMR)
data(gwas_catalog)
head(gwas_catalog)
Carotid_artery_stenosis_gwas<-
subset(gwas_catalog,
grepl("Palmer", Author) &
Phenotype == "Carotid artery stenosis")

exp_dat<- format_data(Carotid_artery_stenosis_gwas)

But it didin't work. Who knows the problem? I am looking forward to your reply.

[yanhuayizha]

While the following example which given by the guide can work, I do not know where is wrong above.
bmi_gwas<-
subset(gwas_catalog,
grepl("Speliotes", Author) &
Phenotype == "Body mass index")
bmi_exp_dat <- format_data(bmi_gwas)