# How to write 2 parallel arrows in the xymatrix environment?

I want to draw 2 parallel arrows in the xy matrix environment.

Basically instead of the standard arrow (\ar[r]), I want to have something like \begin{smallmatrix}\longrightarrow\\\longrightarrow\end{smallmatrix}.

I tried leaving the arrow blank and just writing $$\xymatrix{\begin{smallmatrix}\longrightarrow\\\longrightarrow\end{smallmatrix}}$$, but its not working.

Edit: I need it to write two simplicial objects and arrows between them.

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$\xymatrix{ A \ar@<-.5ex>[r] \ar@<.5ex>[r] & B }$