Having Issues with Igraph (error: in bipartite.mapping(g): Not a graph object)

Hello, I am trying to learn r studio and am following the following tutorial. RPubs - Bipartite/Two-Mode Networks in igraph.

I am getting the above mentioned error. The data I downloaded directly for the tutorial, so I'm not sure what the issue is. Any help in this regard is appreciated. Here is my code and what I get returned.

I am using RSTUDIO version 1.4.1717

davis <- read.csv("davis.csv", header=FALSE)
head(davis)
V1 V2
1 EVELYN 1
2 EVELYN 2
3 EVELYN 3
4 EVELYN 4
5 EVELYN 5
6 EVELYN 6
bipartite.mapping(davis)
Error in bipartite.mapping(davis) : Not a graph object