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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 get_request_token(
        cls, consumer_key, redirect_uri='http://example.com/', state=None
    ):
        '''
        Returns the request token that can be used to fetch the access token

        '''
        headers = {
            'X-Accept': 'application/json',
        }
        url = 'https://getpocket.com/v3/oauth/request'
        payload = {
            'consumer_key': consumer_key,
            'redirect_uri': redirect_uri,
        }

        if state:
            payload['state'] = state

        return cls._make_request(url, payload, headers)[0]['code']