f ∘ g
g ⨟ f
compose(f, g)
opcompose(g, f)
Composition of morphisms.  ∘ is the operator defined in Base.
CompositionsBase.jl defines the opposite composition operator ⨟ as
⨟(fs...) = ∘(reverse(fs)...)
and also the ASCII aliases compose and opcompose.
As ⨟, compose, and opcompose are all defined in terms of ∘,
single-argument call is the identity function.
julia> using CompositionsBase
julia> tuple ∘ inv === compose(tuple, inv) === inv ⨟ tuple === opcompose(inv, tuple)
true
julia> ∘(tuple) === compose(tuple) === ⨟(tuple) === opcompose(tuple) === tuple
true