def get_records():

    """ Get paths for data in data/mit/ directory """

    #Download if doesn't exist

    # There are 3 files for each record

    # *.atr is one of them

    paths = glob('/path/to/MITDB/dataset/*.atr')

    # Get rid of the extension

    paths = [path[:-4] for path in paths]

    paths.sort()

    return paths

def beat_annotations(annotation):

    """ Get rid of non-beat markers """

    """'N' for normal beats. Similarly we can give the input 'L' for left bundle branch block beats. 'R' for right bundle branch block

        beats. 'A' for Atrial premature contraction. 'V' for ventricular premature contraction. '/' for paced beat. 'E' for Ventricular

        escape beat."""

    good = ['N']   

    ids = np.in1d(annotation.symbol, good)

    # We want to know only the positions

    beats = annotation.sample[ids]

    return beats

 def segmentation(records):

    Normal = []

    for e in records:

        signals, fields = wfdb.rdsamp(e, channels = [0]) 

        ann = wfdb.rdann(e, 'atr')

        good = ['N']

        ids = np.in1d(ann.symbol, good)

        imp_beats = ann.sample[ids]

        beats = (ann.sample)

        for i in imp_beats:

            beats = list(beats)

            j = beats.index(i)

            if(j!=0 and j!=(len(beats)-1)):

                x = beats[j-1]

                y = beats[j+1]

                diff1 = abs(x - beats[j])//2

                diff2 = abs(y - beats[j])//2

                Normal.append(signals[beats[j] - diff1: beats[j] + diff2, 0])

    return Normal