I've used this code before to get sequences but not it does not seem to work. I have updated Bioconductor and BiomaRt to their latest versions.

When I run this code (where genes is a dataframe of one column with my genes of interest (official gene symbol):

ensembl <- useMart("ensembl", dataset = "mmusculus_gene_ensembl")
seq <- getSequence(id = genes,
                   type = "mgi_symbol",
                   seqType = "coding",
                   mart = ensembl)

I get the following error:

Error in paste("no getSequence method for objects of class:", class(object)) :
  argument "object" is missing, with no default

Any ideas what I might be doing wrong? I don't think one of my other loaded packages is interfering but it might be the case...

Session info:

R version 3.3.2 (2016-10-31)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 16.04.1 LTS

locale:
 [1] LC_CTYPE=en_US.UTF-8          LC_NUMERIC=C                 
 [3] LC_TIME=en_US.UTF-8           LC_COLLATE=en_US.UTF-8       
 [5] LC_MONETARY=en_US.UTF-8       LC_MESSAGES=en_US.UTF-8      
 [7] LC_PAPER=en_US.UTF-8          LC_NAME=en_US.UTF-8          
 [9] LC_ADDRESS=en_US.UTF-8        LC_TELEPHONE=en_US.UTF-8     
[11] LC_MEASUREMENT=en_US.UTF-8    LC_IDENTIFICATION=en_US.UTF-8

attached base packages:
 [1] grid      stats4    parallel  stats     graphics  grDevices utils     datasets
 [9] methods   base     

other attached packages:
 [1] BiocInstaller_1.24.0 gridExtra_2.2.1      seqinr_3.3-3         org.Hs.eg.db_3.4.0  
 [5] mgu74a.db_3.2.3      org.Mm.eg.db_3.4.0   AnnotationDbi_1.36.0 Biobase_2.34.0      
 [9] xlsx_0.5.7           xlsxjars_0.6.1       rJava_0.9-8          magrittr_1.5        
[13] biomaRt_2.30.0       Biostrings_2.42.0    XVector_0.14.0       IRanges_2.8.1       
[17] S4Vectors_0.12.0     BiocGenerics_0.20.0  stargazer_5.2        reshape2_1.4.2      
[21] ggplot2_2.2.0       

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.8      plyr_1.8.4       bitops_1.0-6     tools_3.3.2      zlibbioc_1.20.0
 [6] RSQLite_1.1      tibble_1.2       gtable_0.2.0     DBI_0.5-1        stringr_1.1.0   
[11] ade4_1.7-4       XML_3.98-1.5     scales_0.4.1     assertthat_0.1   colorspace_1.3-1
[16] labeling_0.3     stringi_1.1.2    RCurl_1.95-4.8   lazyeval_0.2.0   munsell_0.4.3 

You may have been able to use a data.frame in the past, but a quick look at the current help will explain the problem:

    id: An identifier or vector of identifiers.

And a data.frame is categorically not a vector.