# File lib/parseconfig.rb, line 133
  def add(param_name, value)
    if value.class == Hash
      if self.params.has_key?(param_name)
        if self.params[param_name].class == Hash
          self.params[param_name].merge!(value)
        elsif self.params.has_key?(param_name)
          if self.params[param_name].class != value.class
            raise ArgumentError, "#{param_name} already exists, and is of different type!"
          end
        end
      else
        self.params[param_name] = value
      end
      if ! self.groups.include?(param_name)
        self.groups.push(param_name)
      end
    else
      self.params[param_name] = value
    end
  end