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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 UploadUsers(self, hash_algorithm, hash_key, accounts):
 """Uploads multiple users to Gitkit server. Args: hash_algorithm: string, the hash algorithm. hash_key: array, raw key of the hash algorithm. accounts: list of GitkitUser. Returns: A dict of failed accounts. The key is the index of the 'accounts' list, starting from 0. """

    return self.rpc_helper.UploadAccount(hash_algorithm,
                                         base64.urlsafe_b64encode(hash_key),
                                         [GitkitUser.ToRequest(i) for i in accounts])