add one new dec file for event type 17574081
Decay file for B_s20 => K- (B+ -> (D~0 -> K0 pi+ pi-) mu+ nu_mu) decay as a background for B_s20 = K- (B+ -> rho0 mu+ nu_mu)
Decay file for B_s20 => K- (B+ -> (D~0 -> K0 pi+ pi-) mu+ nu_mu) decay as a background for B_s20 = K- (B+ -> rho0 mu+ nu_mu)