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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def Build(self):
 """Builds a client config dictionary used in the OAuth 2.0 flow."""

    if all((self.client_type, self.client_id, self.client_secret,
            self.auth_uri, self.token_uri)):
      client_config = {
          self.client_type: {
              'client_id': self.client_id,
              'client_secret': self.client_secret,
              'auth_uri': self.auth_uri,
              'token_uri': self.token_uri
          }
      }
    else:
      raise ValueError('Required field is missing.')

    return client_config