diff --git a/duniterpy/constants.py b/duniterpy/constants.py
index c76c99621b0c8b9c98ac4d4d5ab329b617dc4bf5..626f338238a3340bde5678c8520540420c8894f4 100644
--- a/duniterpy/constants.py
+++ b/duniterpy/constants.py
@@ -8,8 +8,10 @@ BLOCK_ID_REGEX = "[0-9]+"
 BLOCK_UID_REGEX = "{block_id_regex}-{block_hash_regex}".format(
     block_id_regex=BLOCK_ID_REGEX, block_hash_regex=BLOCK_HASH_REGEX
 )
-CONDITIONS_REGEX = "(&&|\\|\\|| |[()]|(SIG\\({pubkey_regex}\\)|(XHX\\({hash_regex}\\))))*".format(
-    pubkey_regex=PUBKEY_REGEX, hash_regex=HASH_REGEX
+CONDITIONS_REGEX = (
+    "(&&|\\|\\|| |[()]|(SIG\\({pubkey_regex}\\)|(XHX\\({hash_regex}\\))))*".format(
+        pubkey_regex=PUBKEY_REGEX, hash_regex=HASH_REGEX
+    )
 )
 IPV4_REGEX = (
     "(?:(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){3}(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4]["
diff --git a/duniterpy/documents/block.py b/duniterpy/documents/block.py
index 7cf69ef45cd02fd4efd5616250a83406876e7a3a..62a4e27389bb462397273c2052bd428038d4b4bd 100644
--- a/duniterpy/documents/block.py
+++ b/duniterpy/documents/block.py
@@ -18,46 +18,46 @@ BlockType = TypeVar("BlockType", bound="Block")
 
 class Block(Document):
     """
-The class Block handles Block documents.
-
-.. note:: A block document is specified by the following format :
-
-    | Version: VERSION
-    | Type: Block
-    | Currency: CURRENCY
-    | Nonce: NONCE
-    | Number: BLOCK_NUMBER
-    | PoWMin: NUMBER_OF_ZEROS
-    | Time: GENERATED_ON
-    | MedianTime: MEDIAN_DATE
-    | UniversalDividend: DIVIDEND_AMOUNT
-    | Issuer: ISSUER_KEY
-    | PreviousHash: PREVIOUS_HASH
-    | PreviousIssuer: PREVIOUS_ISSUER_KEY
-    | Parameters: PARAMETERS
-    | MembersCount: WOT_MEM_COUNT
-    | Identities:
-    | PUBLIC_KEY:SIGNATURE:TIMESTAMP:USER_ID
-    | ...
-    | Joiners:
-    | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
-    | ...
-    | Actives:
-    | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
-    | ...
-    | Leavers:
-    | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
-    | ...
-    | Excluded:
-    | PUBLIC_KEY
-    | ...
-    | Certifications:
-    | PUBKEY_FROM:PUBKEY_TO:BLOCK_NUMBER:SIGNATURE
-    | ...
-    | Transactions:
-    | COMPACT_TRANSACTION
-    | ...
-    | BOTTOM_SIGNATURE
+    The class Block handles Block documents.
+
+    .. note:: A block document is specified by the following format :
+
+        | Version: VERSION
+        | Type: Block
+        | Currency: CURRENCY
+        | Nonce: NONCE
+        | Number: BLOCK_NUMBER
+        | PoWMin: NUMBER_OF_ZEROS
+        | Time: GENERATED_ON
+        | MedianTime: MEDIAN_DATE
+        | UniversalDividend: DIVIDEND_AMOUNT
+        | Issuer: ISSUER_KEY
+        | PreviousHash: PREVIOUS_HASH
+        | PreviousIssuer: PREVIOUS_ISSUER_KEY
+        | Parameters: PARAMETERS
+        | MembersCount: WOT_MEM_COUNT
+        | Identities:
+        | PUBLIC_KEY:SIGNATURE:TIMESTAMP:USER_ID
+        | ...
+        | Joiners:
+        | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
+        | ...
+        | Actives:
+        | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
+        | ...
+        | Leavers:
+        | PUBLIC_KEY:SIGNATURE:NUMBER:HASH:TIMESTAMP:USER_ID
+        | ...
+        | Excluded:
+        | PUBLIC_KEY
+        | ...
+        | Certifications:
+        | PUBKEY_FROM:PUBKEY_TO:BLOCK_NUMBER:SIGNATURE
+        | ...
+        | Transactions:
+        | COMPACT_TRANSACTION
+        | ...
+        | BOTTOM_SIGNATURE
 
     """
 
diff --git a/duniterpy/documents/membership.py b/duniterpy/documents/membership.py
index ddf245b7fd42533014a19190f83d2e8adb366372..632a02216270e0057525714dabfb0ed1a6e361c4 100644
--- a/duniterpy/documents/membership.py
+++ b/duniterpy/documents/membership.py
@@ -16,16 +16,16 @@ MembershipType = TypeVar("MembershipType", bound="Membership")
 
 class Membership(Document):
     """
-.. note:: A membership document is specified by the following format :
-
-    | Version: VERSION
-    | Type: Membership
-    | Currency: CURRENCY_NAME
-    | Issuer: ISSUER
-    | Block: NUMBER-HASH
-    | Membership: MEMBERSHIP_TYPE
-    | UserID: USER_ID
-    | CertTS: CERTIFICATION_TS
+    .. note:: A membership document is specified by the following format :
+
+        | Version: VERSION
+        | Type: Membership
+        | Currency: CURRENCY_NAME
+        | Issuer: ISSUER
+        | Block: NUMBER-HASH
+        | Membership: MEMBERSHIP_TYPE
+        | UserID: USER_ID
+        | CertTS: CERTIFICATION_TS
 
     """
 
diff --git a/duniterpy/documents/peer.py b/duniterpy/documents/peer.py
index bc26cdbc0ed5dcea2a1a65cca1b1c948bf502e38..78e5857337079d9e1556d86b71975ff969892b64 100644
--- a/duniterpy/documents/peer.py
+++ b/duniterpy/documents/peer.py
@@ -12,18 +12,18 @@ PeerType = TypeVar("PeerType", bound="Peer")
 
 class Peer(Document):
     """
-.. note:: A peer document is specified by the following format :
-
-    | Version: VERSION
-    | Type: Peer
-    | Currency: CURRENCY_NAME
-    | PublicKey: NODE_PUBLICKEY
-    | Block: BLOCK
-    | Endpoints:
-    | END_POINT_1
-    | END_POINT_2
-    | END_POINT_3
-    | [...]
+    .. note:: A peer document is specified by the following format :
+
+        | Version: VERSION
+        | Type: Peer
+        | Currency: CURRENCY_NAME
+        | PublicKey: NODE_PUBLICKEY
+        | Block: BLOCK
+        | Endpoints:
+        | END_POINT_1
+        | END_POINT_2
+        | END_POINT_3
+        | [...]
 
     """
 
diff --git a/duniterpy/documents/transaction.py b/duniterpy/documents/transaction.py
index a4cfc8ee4817d4668a531eb737ad59f3846b6fe6..f0f6447ea6da002e7ddfa604ee5d14893cbc7e7a 100644
--- a/duniterpy/documents/transaction.py
+++ b/duniterpy/documents/transaction.py
@@ -48,10 +48,10 @@ InputSourceType = TypeVar("InputSourceType", bound="InputSource")
 
 class InputSource:
     """
-    A Transaction INPUT
+        A Transaction INPUT
 
-.. note:: Compact :
-    INDEX:SOURCE:FINGERPRINT:AMOUNT
+    .. note:: Compact :
+        INDEX:SOURCE:FINGERPRINT:AMOUNT
 
     """
 
@@ -448,36 +448,36 @@ TransactionType = TypeVar("TransactionType", bound="Transaction")
 
 class Transaction(Document):
     """
-.. note:: A transaction document is specified by the following format :
-
-    | Document format :
-    | Version: VERSION
-    | Type: Transaction
-    | Currency: CURRENCY_NAME
-    | Issuers:
-    | PUBLIC_KEY
-    | ...
-    | Inputs:
-    | INDEX:SOURCE:NUMBER:FINGERPRINT:AMOUNT
-    | ...
-    | Outputs:
-    | PUBLIC_KEY:AMOUNT
-    | ...
-    | Comment: COMMENT
-    | ...
-    |
-    |
-    | Compact format :
-    | TX:VERSION:NB_ISSUERS:NB_INPUTS:NB_OUTPUTS:HAS_COMMENT
-    | PUBLIC_KEY:INDEX
-    | ...
-    | INDEX:SOURCE:FINGERPRINT:AMOUNT
-    | ...
-    | PUBLIC_KEY:AMOUNT
-    | ...
-    | COMMENT
-    | SIGNATURE
-    | ...
+    .. note:: A transaction document is specified by the following format :
+
+        | Document format :
+        | Version: VERSION
+        | Type: Transaction
+        | Currency: CURRENCY_NAME
+        | Issuers:
+        | PUBLIC_KEY
+        | ...
+        | Inputs:
+        | INDEX:SOURCE:NUMBER:FINGERPRINT:AMOUNT
+        | ...
+        | Outputs:
+        | PUBLIC_KEY:AMOUNT
+        | ...
+        | Comment: COMMENT
+        | ...
+        |
+        |
+        | Compact format :
+        | TX:VERSION:NB_ISSUERS:NB_INPUTS:NB_OUTPUTS:HAS_COMMENT
+        | PUBLIC_KEY:INDEX
+        | ...
+        | INDEX:SOURCE:FINGERPRINT:AMOUNT
+        | ...
+        | PUBLIC_KEY:AMOUNT
+        | ...
+        | COMMENT
+        | SIGNATURE
+        | ...
 
     """
 
@@ -856,8 +856,7 @@ Currency: {1}
         ...
         PUBLIC_KEY:AMOUNT
         ...
-        COMMENT
-"""
+        COMMENT"""
         doc = "TX:{0}:{1}:{2}:{3}:{4}:{5}:{6}\n".format(
             self.version,
             len(self.issuers),
diff --git a/pyproject.toml b/pyproject.toml
index 9075982aad00d3a19e39155fbc2c3109aa1e7290..17e1f9a4d8beffd7cf485821b58d8986116e3960 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,7 @@ libnacl = "^1.6.1"
 pyaes = "^1.6.1"
 
 [tool.poetry.dev-dependencies]
-black = { version = "^19.3b0", python = "^3.6" }
+black = { version = "^20.8b1", python = "^3.6" }
 mypy = "^0.730"
 pylint = "^2.4.2"
 sphinx = "^3.0.2"