m@(Method traits) ** n@(Method traits)
"Answers a new Method whose effect is that of calling the first method
on the results of the second method applied to whatever arguments are passed.
This composition is associative, i.e. (a ** b) ** c = a ** (b ** c).
When the second method, n, does not take a *rest option or the first takes
more than one input, then the output is chunked into groups for its
consumption. E.g.:
#; `er ** #; `er applyTo: {'a'. 'b'. 'c'. 'd'} => 'abcd'
#; `er ** #name `er applyTo: {#a. #/}. => 'a/'"
[
  n acceptsAdditionalArguments \/ [m arity = 1]
    ifTrue:
      [[| *args | m applyTo: {n applyTo: args}]]
    ifFalse:
      [[| *args |
        m applyTo:
          ([| :stream |
             args do: [| *each | stream nextPut: (n applyTo: each)]
                  inGroupsOf: n arity] writingAs: {})]]
].

#**`er asMethod: #compose: on: {Method traits. Method traits}.