Fix lint errors.

csv2sql/core/prefetching.py

@@ -4,7 +4,7 @@
 import tempfile
 
 
-class RewindableFileIterator(object):
+class RewindableFileIterator:
     """A file iterator class that can be rewinded.
     An instances of this class can create a temporary file
     and should be closed by `close()` or using `with` statement.

csv2sql/core/type_inference.py

@@ -104,9 +104,8 @@ def _always_true(_):
 
 
 def _create_any_predicate(args):
-    if len(args) != 0:
+    if args:
         raise InterpretationError('Match predicate takes no argument.')
-
     return _always_true
 
 
@@ -141,11 +140,7 @@ def interpret_predicate(obj):
             'Predicate type`{0}` is invalid'.format(predicate_type))
 
     args = obj.get('args', [])  # `args` is an optional value.
-    if (
-            isinstance(args, str) or
-            isinstance(args, bytes) or
-            not hasattr(args, '__iter__')
-    ):
+    if isinstance(args, (str, bytes)) or not hasattr(args, '__iter__'):
         args = [args]
 
     predicate = predicate_generator(args)  # Can raise InterpretationError.
@@ -163,7 +158,7 @@ def interpret_patterns(obj):
     return [_interpret_one_type_pattern(item) for item in obj]
 
 
-class TypeInferrer(object):
+class TypeInferrer:
     """Infers the type while reading items."""
 
     def __init__(self, patterns, null_value=_DEFAULT_NULL_VALUE):
@@ -197,7 +192,7 @@ def type_name(self):
         return self._current[0]
 
 
-class _Inference(object):
+class _Inference:
     def __init__(self, index, patterns, null_value):
         """Initialize."""
         self._index = int(index)

csv2sql/main.py

@@ -8,7 +8,7 @@
 
 import yaml
 
-import csv2sql.meta as meta
+import csv2sql.meta
 import csv2sql.queryengines.psql
 from csv2sql.core.error import InterpretationError
 from csv2sql.core.my_logging import get_logger
@@ -106,6 +106,8 @@ def _decide_patterns(args):
     try:
         with open(pattern_file_path) as pattern_file:
             return yaml.load(pattern_file)
+    # pylint: disable=try-except-raise
+    # since this flow is correct.
     except IOError:
         raise
     except TypeError as error:
@@ -131,7 +133,7 @@ def _parse_column_type(column_type):
     return index, type_name
 
 
-class _ArgsInterfaces(object):
+class _ArgsInterfaces:
     # pylint: disable=too-few-public-methods
     # since this class is an namespace.
     # readable.
@@ -221,7 +223,7 @@ def parse_args(arguments):
         description='Convert CSV data into an SQL dump.')
     parser.add_argument(
         '-v', '--version', action='version',
-        version='%(prog)s {0}'.format(meta.__version__))
+        version='%(prog)s {0}'.format(csv2sql.meta.__version__))
 
     subparsers = parser.add_subparsers(
         title='target', description='What to dump.')

csv2sql/queryengines/psql.py

@@ -84,7 +84,7 @@
 _LINE_TERMINATOR = '\n'
 
 
-class WriterWrapper(object):
+class WriterWrapper:
     """CSV writer wrapper class to escape the special strings."""
 
     def __init__(self, stream, *args, **kwargs):