less jumps syntax error on 'transition-timing function'

I'm just converting a alredy made CSS file into a LESS and would like to know why cant I add transition-timing funct开发者_JS百科ion in the less stylesheet

the code

-webkit-transition-timing function: linear, ease-in;
-moz-transition-timing function: linear, ease-in; 
transition-timing function: linear, ease-in;

the error

the reason?

1) You're missing the - before function.

2) You can only define one value for *-transition-timing-function.

CSS

transition-timing-function: ease-in;
-o-transition-timing-function: ease-in;
-moz-transition-timing-function: ease-in;
-webkit-transition-timing-function: ease-in;