Fix minor PEP8 issues

import pandas as pd

class STSB_Dataset():

class STSB_Dataset:

    def __init__(self, path):

        self.data = []

        self.labels = []

        for line in dataset:

            datapoint = line.split('\t')

            score = float(datapoint[4])

            self.data.append([st1, st2])

            self.labels.append(score)

        # Store as a list of dicts, conforming to self.spec()

        self._examples = [{

          'sentence1': dp[0],