can`t add new font to imgui

[escadrym]

Hi guys i`m just started to learning imgui, i want to add new font, but i can`t due to exception that told "Assertion failed! Expression:0",
below code how i`m trying to do this, calling this after initialization and ImGui::NewFrame()

	
        ImGuiIO& io = ImGui::GetIO( );
	std::string path = "C:\folder\font.ttf"; 
	ImFont* new_font = io.Fonts->AddFontFromFileTTF( path.c_str( ), 16.0f );
	ImGui::PushFont( new_font );