CSV files are loaded several times if they are too large

import apache_beam as beam
import apache_beam.io.filebasedsource
import csv


class CsvFileSource(apache_beam.io.filebasedsource.FileBasedSource):
 def read_records(self, file_name, range_tracker):
     with open(file_name, 'r') as file:
        reader = csv.DictReader(file)
        print("Load CSV file")
           for rec in reader:
              yield rec


if __name__ == '__main__':
 with beam.Pipeline() as p:
 count_feature = (p
           | 'create' >> beam.io.Read(CsvFileSource("myFile.csv"))
           | 'count element' >> beam.combiners.Count.Globally()
           | 'Print' >> beam.Map(print)
 )