A directed cograph_network, or the input format when
keep_format = TRUE.
Arguments
x
Network input.
mode
"mutual" (default) creates an arc in both directions for
every undirected edge; "arbitrary" keeps one arc per edge, running
from the lower node index to the higher.
keep_format
Logical. Return the input format when TRUE.
directed
Logical or NULL. Directedness to read the input with.