You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: OSL_MRP.m
    path of file: ./repos/OMEGA/source
    
    the code of the file until where you have to start completion: function x_mrp = OSL_MRP(options)
%OSL_MRP One-Step Late algorithm with Median Root Prior reconstruction.
%   Implements the OSL_MRP reconstruction on input PET data.
%   See main_nongate.m for options-variables.
%
%   x_mrp = OSL_MRP(options) returns the OSL_MRP reconstructions for all

    
function x_mrp = OSL_MRP(options)
%OSL_MRP One-Step Late algorithm with Median Root Prior reconstruction.
%   Implements the OSL_MRP reconstruction on input PET data.
%   See main_nongate.m for options-variables.
%
%   x_mrp = OSL_MRP(options) returns the OSL_MRP reconstructions for all
%   iterations, including the initial value.

if iscell(options.SinM)
    Sino = options.SinM{1};
    Sino = Sino(:);
else
    Sino = options.SinM;
    Sino = Sino(:);
end