class Sass::Tree::Visitors::Convert

def query_interp_to_src(interp)

values in query expressions.
Like interp_to_src, but removes the unnecessary `#{}` around the keys and 
def query_interp_to_src(interp)
  interp = interp.map do |e|
    next e unless e.is_a?(Sass::Script::Tree::Literal)
    next e unless e.value.is_a?(Sass::Script::Value::String)
    e.value.value
  end
  interp_to_src(interp)
end