//Get the value for justify-content
@function getJustify($arg){
$justify: (
  'sa':space-around,
  'sb':space-between,
  'se':space-evenly,
  'c':center,
  'fs':flex-start,
  'fe':flex-end
);

@each $key,$value in $justify{
  @if($key == $arg){
    @return $value;
  }
}
}

//Get the value for align-items
@function checkAlign($arg){
$align: (
  'b':baseline,
  's':stretch,
  'c':center,
  'fs':flex-start,
  'fe':flex-end
);

@each $key,$value in $align{
  @if($key == $arg){
    @return $value;
  }
}
}

//Display flex
@mixin d-flex(){
  display: flex;
  @content
}

//Applied example
div{
  @include d-flex{
    justify-content: getJustify(c);
    align-content: getAlign(c);
  }
}