It's just DoReadyCheck(), no SlashCmdList for that. The colored functions I mentioned are exactly how they are. You're also missing "elseif".
Lua Code:
Button:SetScript("OnClick", function()
if command=="/pull 6" then
SlashCmdList.DEADLYBOSSMODSPULL(6)
elseif command=="/readycheck" then
DoReadyCheck()
else
Open_chat(command)
end
end)