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: fracInt.m
    path of file: ./repos/chebfun/@chebtech
    
    the code of the file until where you have to start completion: function g = fracInt(f, mu, b)
%FRACINT  Fractional integral of a CHEBTECH. 
%   G = FRACINT(F, MU) returns the smooth part, G, of the order MU fractional
%   integral of the CHEBTECH object F. That is, J^{MU}(F(x)) = (1+x)^MU * G.
%   MU is assumed to be in the range (0,1).
%

    
function g = fracInt(f, mu, b)
%FRACINT  Fractional integral of a CHEBTECH. 
%   G = FRACINT(F, MU) returns the smooth part, G, of the order MU fractional
%   integral of the CHEBTECH object F. That is, J^{MU}(F(x)) = (1+x)^MU * G.
%   MU is assumed to be in the range (0,1).
%
%   G = FRACINT(F, MU, B) is similar, but returns the smoothpart of the
%   fractional integral of the (1+x)^B*F. That is, J^{MU}((1+x)^B*F(x)) =
%   (1+x)^(MU+B) * G(x). 
%
%   The algorithm used to is to expand F in the Legend