code: def read(self):
          
          companies = []
          with open(self.file) as f:
              reader = unicodecsv.reader(f)
              for line in reader:
                  if len(line) >= 1:
                      cnpj = self.format(line[0])
                      if self.valid(cnpj):
                          companies.append(cnpj)
          return companies
docs: Reads data from the CSV file.