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: roots.m
    path of file: ./repos/chebfun/@chebtech
    
    the code of the file until where you have to start completion: function out = roots(f, varargin)
%ROOTS   Roots of a CHEBTECH in the interval [-1,1].
%   ROOTS(F) returns the real roots of th
    
function is zero, then place a root in the middle:
                r = 0;
            else
                % Else return empty:
                r = [];
            end
            
        % Trivial case, n == 1:
        elseif ( n == 1 )

            % If the function is zero, then place a root in the middle:
            if ( c(1) == 0 && rootsPref.zeroFun )
                r = 0;
            else
                % Else return empty:
                r = [];
            end

        % Trivial case, n == 2:
        elseif ( n == 2 )

            % Is the root in [-1,1]?
            r = -c(1)/c(2);
            if ( ~rootsPref.all )
                if ( (abs(imag(r)) > htol) || ...
                     (r < -(1 + htol)) || ...
                     (r > (1 + htol)) )
                    r = [];
                else
                    r = max(min(real(r), 1), -1);
                end