diff --git a/duniterpy/helpers/blockchain.py b/duniterpy/helpers/blockchain.py
index f6c8f8a8670dd61f1a0ff0949bf9902222d99509..71fcca316e79b34ae472eb2cc048c0b5def52cc5 100644
--- a/duniterpy/helpers/blockchain.py
+++ b/duniterpy/helpers/blockchain.py
@@ -13,35 +13,6 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-"""
-Copyright  2014-2020 Vincent Texier <vit@free.fr>
-
-DuniterPy is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-DuniterPy is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""
-
-
-# imports locally stored blockchain in the chunk format
-# example usage :
-# ```
-# from duniterpy.helpers.blockchain import load
-# bc = load() # gets blockchain iterator
-# b = next(bc) # gets block
-# b.number # should return 0
-# next(bc).number # should return 1 (and so on)
-# ```
-
-
 import json
 import pathlib
 
@@ -66,7 +37,7 @@ class JsonBlockchain:
         """parse a json chunk file"""
         with open(
             self.folder.joinpath(
-                "chunk_" + str(self.current_chunk) + "-" + str(CHUNK_SIZE) + ".json"
+                f"chunk_{str(self.current_chunk)}-{str(CHUNK_SIZE)}.json"
             )
         ) as f:
             s = f.read()
diff --git a/examples/load_local_blockchain.py b/examples/load_local_blockchain.py
index 2b95c1d52b4b334c2cafb3e2f6c58223b286dc04..a5a563ea5d471cbf3bbbb775ef6e44361b0b95e9 100644
--- a/examples/load_local_blockchain.py
+++ b/examples/load_local_blockchain.py
@@ -13,37 +13,33 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-"""
-Copyright  2014-2020 Vincent Texier <vit@free.fr>
-
-DuniterPy is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-DuniterPy is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""
-
-
-# this example lets you load locally copy of duniter blockchain into duniterpy objects
-# by default, it searches in ~/.config/duniter/duniter_default/g1/
 
 from duniterpy.helpers.blockchain import load
 
 
 def load_local_blockchain():
-    bc = load()  # gets blockchain iterator
-    b = next(bc)  # gets block
-    print(f"first block number is: {b.number}")  # should return 0
+    """
+    this example lets you load a local copy of
+    duniter blockchain into duniterpy objects
+    by default, it looks in:
+    $HOME/.config/duniter/duniter_default/g1/
+    """
+    # gets blockchain iterator
+    bc = load()
+
+    # gets block
+    b = next(bc)
+
+    # should return 0
     # you can access all properties of this block through it's duniterpy objects attributes
-    print(f"second block number is: {next(bc).number}")  # should return 1
-    print(f"third block number is: {next(bc).number}")  # should return 2
+    print(f"first block number is: {b.number}")
+
+    # should return 1
+    print(f"second block number is: {next(bc).number}")
+
+    # should return 2
+    print(f"third block number is: {next(bc).number}")
+
     # (and so on)