I love the methodswith() function as it lets me quickly find out the functions that take a particular type directly in the REPL without having to look up the type’s documentation on the web.
However, I found it to be too restrictive and it’s missing something. For example,
julia> methodswith(Dict)
29-element Array{Method,1}:
convert(::Type{Dict{K,V}}, d::Dict{K,V}) where {K, V} in Base at dict.jl:208
copy(d::Dict) in Base at dict.jl:134
delete!(h::Dict, key) in Base at dict.jl:558
done(t::Dict, i) in Base at dict.jl:578
empty!(h::Dict{K,V}) where {K, V} in Base at dict.jl:304
get(h::Dict{K,V}, key, default) where {K, V} in Base at dict.jl:478
get(default::Union{Function, Type}, h::Dict{K,V}, key) where {K, V} in Base at dict.jl:483
get!(h::Dict{K,V}, key0, default) where {K, V} in Base at dict.jl:434
get!(default::Union{Function, Type}, h::Dict{K,V}, key::K) where {K, V} in Base at dict.jl:444
get!(default::Union{Function, Type}, h::Dict{K,V}, key0) where {K, V} in Base at dict.jl:436
getindex(h::Dict{K,V}, key) where {K, V} in Base at dict.jl:473
getkey(h::Dict{K,V}, key, default) where {K, V} in Base at dict.jl:527
haskey(h::Dict, key) in Base at dict.jl:505
isempty(t::Dict) in Base at dict.jl:581
launch(manager::Base.Distributed.SSHManager, params::Dict, launched::Array, launch_ntfy::Condition) in Base.Distributed at distributed/managers.jl:121
launch(manager::Base.Distributed.LocalManager, params::Dict, launched::Array, c::Condition) in Base.Distributed at distributed/managers.jl:317
length(t::Dict) in Base at dict.jl:582
next(t::Dict{K,V}, i) where {K, V} in Base at dict.jl:579
pop!(h::Dict, key) in Base at dict.jl:538
pop!(h::Dict, key, default) in Base at dict.jl:543
rand(r::AbstractRNG, t::Dict) in Base.Random at random.jl:374
rand(t::Dict) in Base.Random at random.jl:381
serialize(s::AbstractSerializer, d::Dict) in Base.Serializer at serialize.jl:337
setindex!(h::Dict{K,V}, v0, key::K) where {K, V} in Base at dict.jl:420
setindex!(h::Dict{K,V}, v0, key0) where {K, V} in Base at dict.jl:412
similar(d::Dict{K,V}) where {K, V} in Base at dict.jl:192
similar(d::Dict, ::Type{Pair{K,V}}) where {K, V} in Base at dict.jl:193
sizehint!(d::Dict, newsz) in Base at dict.jl:274
start(t::Dict) in Base at dict.jl:574
In this case, keys() function isn’t returned. As it turns out, keys take the Associative type as its argument rather than Dict. It’s object-oriented, stupid! 
help?> keys
search: keys keytype KeyError haskey getkey WeakKeyDict takebuf_array
keys(a::Associative)
Return an iterator over all keys in a collection. collect(keys(a)) returns an array of keys. Since the keys are stored
internally in a hash table, the order in which they are returned may vary. But keys(a) and values(a) both iterate a and return
the elements in the same order.
julia> a = Dict('a'=>2, 'b'=>3)
Dict{Char,Int64} with 2 entries:
'b' => 3
'a' => 2
julia> collect(keys(a))
2-element Array{Char,1}:
'b'
'a'
I think it would be best if methodswith can return all functions that satisfy the contract. It’s a great utility!
