code: def set_edist_powerlaw_gamma(self, gmin, gmax, delta, ne_cc):
          
          if not (gmin >= 1):
              raise ValueError('must have gmin >= 1; got %r' % (gmin,))
          if not (gmax >= gmin):
              raise ValueError('must have gmax >= gmin; got %r, %r' % (gmax, gmin))
          if not (delta >= 0):
              raise ValueError('must have delta >= 0; got %r, %r' % (delta,))
          if not (ne_cc >= 0):
              raise ValueError('must have ne_cc >= 0; got %r, %r' % (ne_cc,))
  
          self.in_vals[IN_VAL_EDIST] = EDIST_PLG
          self.in_vals[IN_VAL_EMIN] = (gmin - 1) * E0_MEV
          self.in_vals[IN_VAL_EMAX] = (gmax - 1) * E0_MEV
          self.in_vals[IN_VAL_DELTA1] = delta
          self.in_vals[IN_VAL_NB] = ne_cc
          return self
docs: Set the energy distribution function to a power law in the Lorentz factor
  
          **Call signature**
  
          *gmin*
            The minimum Lorentz factor of the distribution
          *gmax*
            The maximum Lorentz factor of the distribution
          *delta*
            The power-law index of the distribution
          *ne_cc*
            The number density of energetic electrons, in cm^-3.
          Returns
            *self* for convenience in chaining.