Each topological group embeds into a duoseparable topological group

A topological group $X$ is called $duoseparable$ if there exists a countable set $S\subseteq X$ such that $SUS=X$ for any neighborhood $U\subseteq of the unit. We construct functor $F$ assigning to each (abelian) duoseparable (abelain-by-cyclic) $FX$, containing an isomorphic copy $X$. In fact, defined on category unital topologized magmas. Also we prove $\sigma$-compact locally compact abelian embeds into abelian-by-countable group.