def check_arity(obj, n_args)
    ary = obj.arity

    if ary >= 0
      n_args == ary
    else
      n_args >= (ary+1).abs
    end
  end
def check_arity(obj, n_args)
    ary = obj.arity

    if ary >= 0
      n_args == ary
    else
      n_args >= (ary+1).abs
    end
  end
def check_arity ( obj , n_args ) ary = obj . arity if ary >= 0 n_args == ary else n_args >= ( ary + 1 ) . abs end end
returns true, if the arity of "obj" matches
returns true if the arity of obj matches