Help with using the igraph library and timeorded in R

I'm using lib 'igraph' and 'timeorded' ( link ) to work with temporal graphs. I have the following temporal graph:

"graph.txt":

a c 1 1

a d 2 2

b d 2 2

c d 3 3

d b 3 3

Mycode:

library(igraph)library(plyr)library(timeordered)g<-read.table("C:/Users/Filli/Desktop/testes/graph.txt", head= TRUE)
g <- generatetonetwork(g)
tdAll <- generatetimedeltas(1,4,3)
graphAgre <- generatenetworkslices(g, tdAll)

The variable 'graphAgre' is the union of all graphs, from 1 to 3 intervals. It represents the following graph:

ButwhenIusethe'degree'functionfor'graph'graphAgre,itgivesmeanerrorstatingthatthegraphAgrevariableisalist,notagraph.HowdoImodifyittobegraph,andso,calculatethedegree?

*Itisnecessarytousethedegreefunction,asIwillalsocalculateclosenessandbetweenness.

**(graphAgre)

[[1]]IGRAPHDNW-45--+attr:name(v/c),weight(e/n),Count(e/n)+edges(vertexnames):[1]a->ca->db->dc->dd->b**typeof(graphAgre)[1]"list"
'