docs: def logo_as_data_uri(self):
          """This TaxPayer's logo as a data uri."""
          _, ext = os.path.splitext(self.logo.file.name)
          with open(self.logo.file.name, 'rb') as f:
              data = base64.b64encode(f.read())
  
          return 'data:image/{};base64,{}'.format(
              ext[1:],  # Remove the leading dot.
              data.decode()
          )