无法使用R中的setup_twitter_oauth（）函数来使用twitter

Question

我正在尝试在R中使用twitteR软件包并安装了所需的软件包，即：install.packages（“twitteR”，“RCurl”，“RJSONIO”，“stringr”）也加载了它们。但是当我尝试使用带有必需参数的setup_twitter_oauth（api_key，api_secret，token，token_secret）命令设置twitter连接时，我收到错误：错误：找不到函数“setup_twitter_oauth”不知道是什么问题。请帮助。

EDIT:
Following is the result of the sessionInfo() command :

> sessionInfo()
R version 3.1.2 (2014-10-31)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_India.1252  LC_CTYPE=English_India.1252   
[3] LC_MONETARY=English_India.1252 LC_NUMERIC=C                  
[5] LC_TIME=English_India.1252    

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

other attached packages:
 [1] Rfacebook_0.5      Rlinkedin_0.1      tm_0.6             NLP_0.1-6         
 [5] wordcloud_2.5      RColorBrewer_1.0-5 XML_3.98-1.1       httpuv_1.3.2      
 [9] devtools_1.6.1     httr_0.5           stringr_0.6.2      RJSONIO_1.3-0     
[13] plyr_1.8.1         twitteR_1.1.7      rjson_0.2.15       ROAuth_0.9.3      
[17] digest_0.6.4       RCurl_1.95-4.4     bitops_1.0-6      

loaded via a namespace (and not attached):
 [1] BradleyTerry2_1.0-5 brglm_0.5-9         car_2.0-22          caret_6.0-37       
 [5] codetools_0.2-9     colorspace_1.2-4    foreach_1.4.2       ggplot2_1.0.0      
 [9] grid_3.1.2          gtable_0.1.2        gtools_3.4.1        iterators_1.0.7    
[13] lattice_0.20-29     lme4_1.1-7          MASS_7.3-35         Matrix_1.1-4       
[17] minqa_1.2.4         munsell_0.4.2       nlme_3.1-118        nloptr_1.0.4       
[21] nnet_7.3-8          parallel_3.1.2      proto_0.3-10        Rcpp_0.11.3        
[25] reshape2_1.4        scales_0.2.4        slam_0.1-32         splines_3.1.2      
[29] tools_3.1.2