Matlab - Error_Undefined function or variable 'makenames'

>> which sin

built-in (C:\Program Files\MATLAB\R2018a\toolbox\matlab\elfun\@double\sin)  % double method

>> which makenames

'makenames' not found.

>> help makenames

NAMES = MAKENAMES('PREFIX',INDEX) creates a M-by-1 cell array of

%    strings, NAMES.  NAMES is generated by appending the string PREFIX

%    with non-negative integers contained in the array INDEX of length M.

%

%    If used for named referencing, PREFIX must contain only letters,

%    numbers and underscores and must begin with a letter, otherwise

%    PREFIX can contain any character.

%

%    MAKENAMES is intended for use with the function ADDCHANNEL/ADDLINE.

>>version

>>help makenames

>>which makenames

function names=makenames(prefix, nums)

%MAKENAMES Generate cell array of names for ADDCHANNEL/ADDLINE.

%

%    NAMES = MAKENAMES('PREFIX',INDEX) creates a M-by-1 cell array of

%    strings, NAMES.  NAMES is generated by appending the string PREFIX

%    with non-negative integers contained in the array INDEX of length M.

%

%    If used for named referencing, PREFIX must contain only letters,

%    numbers and underscores and must begin with a letter, otherwise

%    PREFIX can contain any character.

%

%    MAKENAMES is intended for use with the function ADDCHANNEL/ADDLINE.

%

%    Example:

%     If OBJ is an analog input object, then the following commands

%     creates three channels named 'Chan1', 'Chan2' and 'Chan3',

%     assigned to hardware channels [0 1 2]:

%

%       names=makenames('Chan', [1:3]);

%       addchannel(OBJ, [0:2], names)

%

%    See also DAQHELP, ADDCHANNEL, ADDLINE.

%

function names=makenamescaballero(prefix,index)

if nargin==0

    prefix='Chan';

    index=5:12;

end

k=1;

 for i=index

     names{k,1}=[prefix,num2str(i)];

     k=k+1;

 end

>> names=makenamescaballero('libro',5:10)

>> version

ans =

    '9.3.0.713579 (R2017b)'

names =

  6×1 cell array

    {'libro5' }

    {'libro6' }

    {'libro7' }

    {'libro8' }

    {'libro9' }

    {'libro10'}

>> version

ans =

8.2.0.701 (R2013b)

>> names=makenames('tiempo',5:12)

names =

    'tiempo5'

    'tiempo6'

    'tiempo7'

    'tiempo8'

    'tiempo9'

    'tiempo10'

    'tiempo11'

    'tiempo12'

>> version

ans =

8.2.0.701 (R2013b)

>> names=makenamescaballero('tiempo',5:12)

names =

    'tiempo5'

    'tiempo6'

    'tiempo7'

    'tiempo8'

    'tiempo9'

    'tiempo10'

    'tiempo11'

    'tiempo12'