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: operatorBlock.m
    path of file: ./repos/chebfun/@operatorBlock
    
    the code of the file until where you have to start completion: classdef (InferiorClasses = {?chebfun}) operatorBlock < linBlock
%OPERATORBLOCK   Linear map of function to function.
%   This class is not intended to be called directly by the end user.
%
% See also LINBLOCK, LINOP, CHEBOP, CHEBOPPREF.

% Copyright 2017 by The University of Oxford and The 
    
function Z = zeros(domain)
        %OPERATORBLOCK.ZEROS   Zero operator.
        %   Z = OPERATORBLOCK.ZEROS(DOMAIN) returns the zero operator for
        %   functions on the domain DOMAIN (i.e., the operator that maps all
        %   functions to the zero function on the DOMAIN).
        
            pref = cheboppref;
            if ( nargin == 0 )
                domain = pref.domain;
            end