title: asdict() inside .format() in a Python class
body: <p>How can I use <code>asdict()</code> method inside <code>.format()</code> in oder to unpack the class attributes.
  So that instead of this:</p>
  <pre><code>from dataclasses import dataclass, asdict
  
  @dataclass
  class InfoMessage():
      training_type: str
      duration: float
      distance: float
      message = 'Training type: {}; Duration: {:.3f} ч.; Distance: {:.3f}'
  
      def get_message(self) -&gt; str:
          return self.message.format(self.training_type, self.duration, self.distance)
  </code></pre>
  <p>I could write something like this:</p>
  <pre><code>@dataclass
  class InfoMessage():
      training_type: str
      duration: float
      distance: float
      message = 'Training type: {}; Duration: {:.3f} ч.; Distance: {:.3f}'
  
      def get_message(self) -&gt; str:
          return self.message.format(asdict().keys())
  </code></pre>