importers SyntaxWarning

After removing all *.pyc files

/Users/carlos.vega/dev/scheduling-system/smash/web/importer/csv_tns_visit_import_reader.py:120: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":
/Users/carlos.vega/dev/scheduling-system/smash/web/importer/csv_tns_visit_import_reader.py:172: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":
/Users/carlos.vega/dev/scheduling-system/smash/web/importer/importer.py:75: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":
/Users/carlos.vega/dev/scheduling-system/smash/web/importer/importer.py:94: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":
/Users/carlos.vega/dev/scheduling-system/smash/web/importer/importer.py:117: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":
/Users/carlos.vega/dev/scheduling-system/smash/web/importer/importer.py:132: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if field.get_internal_type() == "CharField" or field.get_internal_type() == "DateField" or field.get_internal_type() is "BooleanField":