Unable to use write in module containing a module with JLD

[djsegal]

trafficstars

jldopen(work_file, "w") do file
  for line in readlines(input_file)
    cur_var, cur_val = map(x -> strip(x), split(line, "="))
    write(file, cur_var, cur_val)
  end
end

gives

ERROR: LoadError: LoadError: LoadError: MethodError: no method matching write(::JLD.JldFile, ::SubString{String}, ::SubString{String})