Minor style fixes

Author: mzinin

test/functions/test_function_format_date.py

@@ -79,4 +79,3 @@ def test_negative_second_argument_none(self):
         with pytest.raises(ExpressionError) as ex:
             self.function.invoke(stack)
         assert 'Invalid arguments' in str(ex.value)
-       

test/test_converter.py

@@ -1,5 +1,5 @@
-from s2e2.error import ExpressionError
 from s2e2.converter import Converter
+from s2e2.error import ExpressionError
 from s2e2.token_type import TokenType
 from s2e2.token import Token
 

test/test_splitter.py

@@ -16,10 +16,6 @@ def teardown(self):
         self.splitter = None
 
 
-    def test_positive_new_splitter(self):
-        pass
-
-
     def test_positive_split_by_comma(self):
         expression = 'A, B'
         expected_tokens = [Token(TokenType.ATOM, 'A'),