a list of expressions (of one or more conditions), each
repeating a step in the sequence.
Details
Steps must be separated by commas (,). ... denotes zero or more
interactions may precede the step that follows, otherwise without ... then
the there must not be any interactions between the adjacent steps in order for the
results to the sequence.
# NOT RUN {a <- Expr(~pagePath == "/home")
b <- Expr(~eventCategory == "Video") &
Expr(~eventAction == "Play")
c <- Expr(~medium == "email")
s <- sequential_segment(list( ..., a, ..., b, c ))
# }