If period of time between start end end is bigger then one year
        We have to create and fetch chunks dates (6 months chunks).

def fetch_chunk_data(self):
        """If period of time between start end end is bigger then one year
        We have to create and fetch chunks dates (6 months chunks)."""
        data = []

        counter = (relativedelta(self.end_date, self.start_date).months / 6) + 1
        months = 0

        for month in range(counter):

            chunk_start_date = self.start_date + relativedelta(months=months)
            chunk_end_date = self.start_date + relativedelta(months=months + 6)

            months += 6

            if chunk_end_date > self.end_date:
                chunk_end_date = self.end_date

            data = data + self.request.send(self.symbol, chunk_start_date, chunk_end_date)

        return data