bimapArrow [ep1, ep2]
= EP { fromEP = mkHsLam [nlVarPat a_RDR, nlVarPat b_RDR] from_body,
toEP = mkHsLam [nlVarPat a_RDR, nlVarPat b_RDR] to_body }
bimapArrow [ep1, ep2]
= EP { fromEP = mkHsLam [nlVarPat a_RDR, nlVarPat b_RDR] from_body,
toEP = mkHsLam [nlVarPat a_RDR, nlVarPat b_RDR] to_body }