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: projectOntoBMCI.m
    path of file: ./repos/chebfun/@spherefun
    
    the code of the file until where you have to start completion: function f = projectOntoBMCI(f)
% PROJECTONTOBMCI  Projection onto BMC-I symmetry.
%
% f = projectOntoBMCI(f) is the orthogonal projection of f onto BMC-I 
% symmetry, i.e., a function that is
% 1. even in theta for every even wave number in lambda;
%
    
function f = projectOntoOddBMCI(f)
% Project a spherefun to have odd BMC-I symmetry, i.e., a spherefun that is
% pi-anti-periodic in lambda and even in theta. The projection is
% orthogonal, i.e., the correction matrix to fix up the structure has the
% smallest possible Frobenius norm.

% Nothing to project
if isempty(f)
    return;
end