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: createRotationOy.m
    path of file: ./repos/matGeom/matGeom/geom3d
    
    the code of the file until where you have to start completion: function trans = createRotationOy(varargin)
%CREATEROTATIONOY Create the 4x4 matrix of a 3D rotation around y-axis.
%
%   TRANS = createRotationOy(THETA);
%   Returns the transform matrix corresponding to a rotation by the angle
%   THETA (in radians) around the Oy axis. A rotation by an angle of PI/2
%   would transform the vector [0 0 1] into the vector [1 0 0].
%
%   The returned matrix has the form:
%   [ cos(THETA)  0  sin(THETA)  0 ]
%   [    0        1       0      0 ]
%   [-sin(THETA)  0  cos(THETA)  0 ]
%   [    0        0       0      1 ]
%
%   TRANS = createRotationOy(ORIGIN, THETA);
%   TRANS = createRotationOy(X0, Y0, Z0, THETA);
%   Also specifies origin of rotation. The result is similar as performing
%   translation(-X0, -Y0, -Z0), rotation, and translation(X0, Y0, Z0).
%
%
%   See also 
%   transforms3d, transformPoint3d, createRotationOx, createRotationOz
%

% ------
% Author: David Legland 

    
function trans = createRotationOy(varargin)
%CREATEROTATIONOY Create the 4x4 matrix of a 3D rotation around y-axis.
%
%   TRANS = createRotationOy(THETA);
%   Returns the transform matrix corresponding to a rotation by the angle
%   THETA (in radians) around the Oy axis. A rotation by an angle of PI/2
%   would transform the vector [0 0 1] into the vector [1 0 0].
%
%   The returned matrix has the form:
%   [ cos(THETA)  0  sin(THETA)  0 ]
%   [    0        1       0      0 ]
%   [-sin(THETA)  0  cos(THETA)  0 ]
%   [    0        0       0      1 ]
%
%   TRANS = createRotationOy(ORIGIN, THETA);
%   TRANS = createRotationOy(X0, Y0, Z0, THETA);
%   Also specifies origin of rotation. The result is similar as performing
%   translation(-X0, -Y0, -Z0), rotation, and translation(X0, Y0, Z0).
%
%
%   See also 
%   transforms3d, transformPoint3d, createRotationOx, createRotationOz
%

% ------
% Author: David Legland 
% E-mail: david.legland@inrae.fr
% Created: 2005-02-18
% Copyright 2005-2023 INRA - TPV URPOI - BIA IMASTE

% default values
dx = 0;
dy = 0;
dz = 0;
theta = 0;

% get input values
if length(varargin) == 1
    % only one argument -> rotation angle
    theta = varargin{1};
    
elseif length(varargin) == 2
    % origin point (as array) and angle
    var = varargin{1};
    dx = var(1);
    dy = var(2);
    dz = var(3);
    theta = varargin{2};
    
elseif length(varargin) == 3
    % origin (x and y) and angle
    dx = varargin{1};
    dy = varargin{2};
    dz = 0;
    theta = varargin{3};
    
elseif length(varargin) == 4
    % origin (x and y) and angle
    dx = varargin{1};
    dy = varargin{2};
    dz = varargin{3};
    theta = varargin{4};
end