title: How does one ignore extra arguments passed to a dataclass?
body: <p>I'd like to create a <code>config</code> <code>dataclass</code> in order to simplify whitelisting of and access to specific environment variables (typing <code>os.environ['VAR_NAME']</code> is tedious relative to <code>config.VAR_NAME</code>). I therefore need to ignore unused environment variables in my <code>dataclass</code>'s <code>__init__</code> function, but I don't know how to extract the default <code>__init__</code> in order to wrap it with, e.g., a function that also includes <code>*_</code> as one of the arguments.</p>
  
  <pre><code>import os
  from dataclasses import dataclass
  
  @dataclass
  class Config:
      VAR_NAME_1: str
      VAR_NAME_2: str
  
  config = Config(**os.environ)
  </code></pre>
  
  <p>Running this gives me <code>TypeError: __init__() got an unexpected keyword argument 'SOME_DEFAULT_ENV_VAR'</code>.</p>