fix linter errors in etcdb/sqlparser/sql_tree.py

[akuzminsky]

• Etcd Database Driver version: 1.0.3

Description

pylint fails on etcdb/sqlparser/sql_tree.py

What I Did

$ pylint etcdb/sqlparser/sql_tree.py
************* Module etcdb.sqlparser.sql_tree
C:  1, 0: Missing module docstring (missing-docstring)
C:  1, 0: Missing class docstring (missing-docstring)
R:  1, 0: Too many instance attributes (11/7) (too-many-instance-attributes)
C: 18, 4: Missing method docstring (missing-docstring)
R:  1, 0: Too few public methods (1/2) (too-few-public-methods)


Report
======
15 statements analysed.

Statistics by type
------------------

+---------+-------+-----------+-----------+------------+---------+
|type     |number |old number |difference |%documented |%badname |
+=========+=======+===========+===========+============+=========+
|module   |1      |NC         |NC         |0.00        |0.00     |
+---------+-------+-----------+-----------+------------+---------+
|class    |1      |NC         |NC         |0.00        |0.00     |
+---------+-------+-----------+-----------+------------+---------+
|method   |2      |NC         |NC         |50.00       |0.00     |
+---------+-------+-----------+-----------+------------+---------+
|function |0      |NC         |NC         |0           |0        |
+---------+-------+-----------+-----------+------------+---------+



Raw metrics
-----------

+----------+-------+------+---------+-----------+
|type      |number |%     |previous |difference |
+==========+=======+======+=========+===========+
|code      |17     |85.00 |NC       |NC         |
+----------+-------+------+---------+-----------+
|docstring |2      |10.00 |NC       |NC         |
+----------+-------+------+---------+-----------+
|comment   |0      |0.00  |NC       |NC         |
+----------+-------+------+---------+-----------+
|empty     |1      |5.00  |NC       |NC         |
+----------+-------+------+---------+-----------+



Duplication
-----------

+-------------------------+------+---------+-----------+
|                         |now   |previous |difference |
+=========================+======+=========+===========+
|nb duplicated lines      |0     |NC       |NC         |
+-------------------------+------+---------+-----------+
|percent duplicated lines |0.000 |NC       |NC         |
+-------------------------+------+---------+-----------+



Messages by category
--------------------

+-----------+-------+---------+-----------+
|type       |number |previous |difference |
+===========+=======+=========+===========+
|convention |3      |NC       |NC         |
+-----------+-------+---------+-----------+
|refactor   |2      |NC       |NC         |
+-----------+-------+---------+-----------+
|warning    |0      |NC       |NC         |
+-----------+-------+---------+-----------+
|error      |0      |NC       |NC         |
+-----------+-------+---------+-----------+



Messages
--------

+-----------------------------+------------+
|message id                   |occurrences |
+=============================+============+
|missing-docstring            |3           |
+-----------------------------+------------+
|too-many-instance-attributes |1           |
+-----------------------------+------------+
|too-few-public-methods       |1           |
+-----------------------------+------------+



Global evaluation
-----------------
Your code has been rated at 6.67/10