Can anyone advise me as to which is wrong: the library, the documentation, or my understanding, in the following:

in ?GenomicFeatures I read:

'metadata(x)': Returns 'x''s metadata in a data frame.

But I find:

> metadata(txdb)
Error in UseMethod("metadata") :
  no applicable method for 'metadata' applied to an object of class "c('TranscriptDb', 'GenomicFeatures')"

# even though txdb is a TranscriptDb, as evidenced:

> txdb
TranscriptDb object:
| Db type: TranscriptDb
| Data source: BioMart
| BioMart database: ensembl
| BioMart database version: ENSEMBL GENES 63 (SANGER UK)
| BioMart dataset: dmelanogaster_gene_ensembl
| BioMart dataset description: Drosophila melanogaster genes (BDGP5.25)
| BioMart dataset version: BDGP5.25
| Full dataset: yes
| transcript_nrow: 23017
| exon_nrow: 71322
| cds_nrow: 60957
| Db created by: GenomicFeatures package from Bioconductor
| Creation time: 2011-07-20 08:14:13 -0500 (Wed, 20 Jul 2011)
| GenomicFeatures version at creation time: 1.4.2
| RSQLite version at creation time: 0.9-4
| DBSCHEMAVERSION: 1.0

> sessionInfo()
R version 2.13.0 (2011-04-13)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

locale:
[1] C

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
[1] biomaRt_2.8.0
 [2] compare_0.2-3
 [3] svUnit_0.7-5
 [4] doMC_1.2.2
 [5] multicore_0.1-5
 [6] foreach_1.3.2
 [7] codetools_0.2-8
 [8] iterators_1.0.4
 [9] ggplot2_0.8.9
[10] reshape_0.8.4
[11] plyr_1.5.2
[12] stringr_0.4
[13] sqldf_0.3-5
[14] chron_2.3-39
[15] gsubfn_0.5-5
[16] proto_0.3-9.2
[17] RSQLite.extfuns_0.0.1
[18] RSQLite_0.9-4
[19] DBI_0.2-5
[20] rtracklayer_1.13.3
[21] RCurl_1.5-0
[22] bitops_1.0-4.1
[23] Rsamtools_1.4.2
[24] GenomicFeatures_1.4.2
[25] BSgenome.Dmelanogaster.UCSC.dm3_1.3.17
[26] BSgenome_1.20.0
[27] Biostrings_2.20.1
[28] GenomicRanges_1.4.6
[29] IRanges_1.10.4

loaded via a namespace (and not attached):
[1] XML_3.4-0    tcltk_2.13.0 tools_2.13.0
>

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