how to call for the value of a variable from another script and perform mathematical operations from it.

here is code for the function that i have written:

function f  = scale(m)
  f = (m*sf)+ao;
end

it gives an error saying : too many output arguments

the code from where I am getting those attributes is as shown below.

data = netcdf.getVar(ncid1,j);
  [varname, xtype, dimid, natt] = netcdf.inqVar(ncid1, j);
  disp(j)
  sf = netcdf.getAtt(ncid1,j,'scale_factor');
  ao = netcdf.getAtt(ncid1,j,'add_offset');