From a29fd7e84f61f6df299faf4d955596edb090a8e7 Mon Sep 17 00:00:00 2001
From: kansi <kansi13@gmail.com>
Date: Fri, 3 Nov 2017 18:37:19 +0530
Subject: [PATCH] Fix variable type check and docstrings

---
 bigchaindb/backend/schema.py |  8 ++++----
 bigchaindb/common/utils.py   | 11 +++--------
 bigchaindb/models.py         |  4 ++--
 3 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/bigchaindb/backend/schema.py b/bigchaindb/backend/schema.py
index 07fe4210..fcad33a6 100644
--- a/bigchaindb/backend/schema.py
+++ b/bigchaindb/backend/schema.py
@@ -108,14 +108,14 @@ def init_database(connection=None, dbname=None):
     create_indexes(connection, dbname)
 
 
-def validate_if_exists_language(obj, key):
+def validate_language_key(obj, key):
     """Validate all nested "language" key in `obj`.
 
        Args:
            obj (dict): dictonary whose "language" key is to be validated.
 
        Returns:
-           None: validation successfull
+           None: validation successful
 
         Raises:
             ValidationError: raises execption incase language is not valid.
@@ -135,7 +135,7 @@ def validate_language(value):
             value (str): language to validated
 
         Returns:
-            None: validation successfull
+            None: validation successful
 
         Raises:
             ValidationError: raises execption incase language is not valid.
@@ -145,4 +145,4 @@ def validate_language(value):
                      'language "{}". If you do not understand this error '
                      'message then please rename key/field "language" to '
                      'something else like "lang".').format(value)
-        raise ValidationError(error_str) from ValueError()
+        raise ValidationError(error_str)
diff --git a/bigchaindb/common/utils.py b/bigchaindb/common/utils.py
index 00621b2e..b21f41d6 100644
--- a/bigchaindb/common/utils.py
+++ b/bigchaindb/common/utils.py
@@ -92,9 +92,8 @@ def validate_all_keys(obj_name, obj, validation_fun):
     """
     for key, value in obj.items():
         validation_fun(obj_name, key)
-        if type(value) is dict:
+        if isinstance(value, dict):
             validate_all_keys(obj_name, value, validation_fun)
-    return
 
 
 def validate_all_value_for_key(obj, key, validation_fun):
@@ -107,18 +106,14 @@ def validate_all_value_for_key(obj, key, validation_fun):
             validation_fun (function): function used to validate the value
             of `key`.
 
-        Returns:
-            None: indicates validation successfull
-
         Raises:
             ValidationError: `validation_fun` will raise this error on failure
     """
     for vkey, value in obj.items():
         if vkey == key:
             validation_fun(value)
-        elif type(value) is dict:
+        elif isinstance(value, dict):
             validate_all_value_for_key(value, key, validation_fun)
-    return
 
 
 def validate_key(obj_name, key):
@@ -139,4 +134,4 @@ def validate_key(obj_name, key):
         error_str = ('Invalid key name "{}" in {} object. The '
                      'key name cannot contain characters '
                      '".", "$" or null characters').format(key, obj_name)
-        raise ValidationError(error_str) from ValueError()
+        raise ValidationError(error_str)
diff --git a/bigchaindb/models.py b/bigchaindb/models.py
index 152a8bcd..8e7a6bde 100644
--- a/bigchaindb/models.py
+++ b/bigchaindb/models.py
@@ -11,7 +11,7 @@ from bigchaindb.common.transaction import Transaction
 from bigchaindb.common.utils import (gen_timestamp, serialize,
                                      validate_txn_obj, validate_key)
 from bigchaindb.common.schema import validate_transaction_schema
-from bigchaindb.backend.schema import validate_if_exists_language
+from bigchaindb.backend.schema import validate_language_key
 
 
 class Transaction(Transaction):
@@ -88,7 +88,7 @@ class Transaction(Transaction):
         validate_transaction_schema(tx_body)
         validate_txn_obj('asset', tx_body['asset'], 'data', validate_key)
         validate_txn_obj('metadata', tx_body, 'metadata', validate_key)
-        validate_if_exists_language(tx_body['asset'], 'data')
+        validate_language_key(tx_body['asset'], 'data')
         return super().from_dict(tx_body)
 
     @classmethod