docs: def create(self, key, value):
          """Atomically create the given key only if the key doesn't exist.
  
          This verifies that the create_revision of a key equales to 0, then
          creates the key with the value.
          This operation takes place in a transaction.
  
          :param key: key in etcd to create
          :param value: value of the key
          :type value: bytes or string
          :returns: status of transaction, ``True`` if the create was
                    successful, ``False`` otherwise
          :rtype: bool
          """
          base64_key = _encode(key)
          base64_value = _encode(value)
          txn = {
              'compare': [{
                  'key': base64_key,
                  'result': 'EQUAL',
                  'target': 'CREATE',
                  'create_revision': 0
              }],
              'success': [{
                  'request_put': {
                      'key': base64_key,
                      'value': base64_value,
                  }
              }],
              'failure': []
          }
          result = self.transaction(txn)
          if 'succeeded' in result:
              return result['succeeded']
          return False