Based on the nuclear attenuation data obtained by the HERMES experiment on
nitrogen and krypton nuclei, it is shown that the nuclear attenuation RMh
can be parametrised in a form of a linear polynomial P1=a11 + τa12, where τ is the formation time, which depends on the energy of the
virtual photon ν and fraction of that energy z carried by the final
hadron. Three widely known parameterizations for τ were used for the
performed fit. The fit parameters a11 and a12 do not depend on ν
and z