std::map kind of implementation in Lua - dictionary

Question

I have std::map which contains list of values associated with a Key. Actual implementation contains many such Keys. Is there a similar way in Lua Table implementation which could hold multiple values for a specific key. If so how to write and read from that table.
I referred the How do I create a Lua Table in C++, and pass it to a Lua function?
I have only access to set and get values which is on my C++ code which was written more generic and cannot create table in C++. (Third party C++ code).
All I have is I can get KeyType, Key, and Value using the
luaState = luaL_newstate();
lua_register(luaState, "getValue", get_value);
lua_register(luaState, "setValue", set_value);.
The C++ code has something like
typedef std::set<const char *> TValueNames;
std::map<const char *, TValueNames> keyValueList;
By referring to Lua document I understood I can create a table with Key as index and assign value as its data. But I need to know how to assign multiple value(data) for one Key.
https://www.lua.org/pil/2.5.html
The example lua script implementation is like,
local keyType = getValue("KeyType");
local Key = getValue("Key");
local Value = getValue("Value");
KeyValueTable = {}
KeyValueTable[Key] = Value;
I need to create something which could hold information like,
["Key1"] = {"Value1,Value2,Value3"};
["Key2"] = {"Value2,Value3,Value4,Value5"};

Answer 1

As you know, a key in a Lua table can only refer to one value, but you can easily make that value a table to hold multiple values. To more faithfully represent the set in the C++ structure, we can make the values into keys in the inner table.
local function setValue(self, key, value)
self[key] = self[key] or {}
self[key][value] = true
end
local function removeValue(self, key, value)
if type(self[key]) == 'table' then
self[key][value] = nil
end
end
local function checkValue(self, key, value)
if type(self[key]) == 'table' then
return self[key][value]
end
end