code: def _dialect(self, filepath):
          
          with open(filepath, self.read_mode) as csvfile:
              sample = csvfile.read(1024)
              dialect = csv.Sniffer().sniff(sample)
              if self.has_header == None:
                  # detect header if header not specified
                  self.has_header = csv.Sniffer().has_header(sample)
              csvfile.seek(0)
          return dialect
docs: returns detected dialect of filepath and sets self.has_header
          if not passed in __init__ kwargs
          Arguments:
              filepath (str): filepath of target csv file