There is provided a computer-implemented method for processing data items for use in training a machine learning model to identify a relationship between the data items. The data items correspond to one or more features of a telecommunications network. For each feature of the one or more features, the corresponding data items are organised into a sequence according to time to obtain at least one sequence of data items. A single sequence of data items having the at least one sequence of data items is encoded to obtain an encoded sequence of data items. The single sequence of data items is encoded with information indicative of a position of data items in the single sequence of data items. The encoded sequence of data items is for use in training the machine learning model to identify the relationship between the data items.