def set(var_hash)
      var_hash.each do |variable_name, value|
        throw :MissingVariable unless @variables_hash.has_key? variable_name

        bv = @variables_hash[variable_name]
        bv.value = value
      end
    end
def set(var_hash)
      var_hash.each do |variable_name, value|
        throw :MissingVariable unless @variables_hash.has_key? variable_name

        bv = @variables_hash[variable_name]
        bv.value = value
      end
    end
Use to set the value for a variety of variables