issue #56 WIP - Fix bug in ws2p/heads document module

duniterpy/documents/ws2p/heads.py

-import attr
 import re
 
+import attr
+
 from ..block import BlockUID
-from ...constants import WS2P_PUBLIC_PREFIX_REGEX, WS2P_PRIVATE_PREFIX_REGEX,\
-    PUBKEY_REGEX, SIGNATURE_REGEX, WS2PID_REGEX, BLOCK_UID_REGEX, ws2p_head_regex
+from ...constants import WS2P_PUBLIC_PREFIX_REGEX, WS2P_PRIVATE_PREFIX_REGEX, WS2P_HEAD_REGEX, \
+    PUBKEY_REGEX, SIGNATURE_REGEX, WS2PID_REGEX, BLOCK_UID_REGEX
 
 
 @attr.s()
 class API:
-    re_inline = re.compile("WS2P({ws2p_private})?({ws2p_public})?"
-                            .format(
+    re_inline = re.compile("WS2P({ws2p_private})?({ws2p_public})?".format(
         ws2p_private=WS2P_PRIVATE_PREFIX_REGEX,
         ws2p_public=WS2P_PUBLIC_PREFIX_REGEX))
 
@@ -37,7 +37,7 @@ class API:
 
 @attr.s()
 class Head:
-    re_inline = re.compile(ws2p_head_regex)
+    re_inline = re.compile(WS2P_HEAD_REGEX)
 
     version = attr.ib(type=int)
 
@@ -64,7 +64,7 @@ class HeadV0:
     re_inline = re.compile("^(WS2P(?:{ws2p_private})?(?:{ws2p_public})?):({head}):({pubkey}):({blockstamp})(?::)?(.*)"
                            .format(ws2p_private=WS2P_PRIVATE_PREFIX_REGEX,
                                    ws2p_public=WS2P_PUBLIC_PREFIX_REGEX,
-                                   head=ws2p_head_regex,
+                                   head=WS2P_HEAD_REGEX,
                                    version="[0-9]+",
                                    pubkey=PUBKEY_REGEX,
                                    blockstamp=BLOCK_UID_REGEX))
@@ -96,9 +96,7 @@ class HeadV0:
 
 @attr.s()
 class HeadV1:
-    re_inline = re.compile("({ws2pid}):" \
-                            "({software}):({software_version}):({pow_prefix})(?::)?(.*)"
-                            .format(
+    re_inline = re.compile("({ws2pid}):({software}):({software_version}):({pow_prefix})(?::)?(.*)".format(
         ws2pid=WS2PID_REGEX,
         software="[A-Za-z-_]+",
         software_version="[0-9]+[.][0-9]+[.][0-9]+",
@@ -137,10 +135,10 @@ class HeadV1:
     def blockstamp(self):
         return self.v0.blockstamp
 
+
 @attr.s
 class HeadV2:
-    re_inline = re.compile("({free_member_room}):({free_mirror_room})(?::)?(.*)"
-                            .format(
+    re_inline = re.compile("({free_member_room}):({free_mirror_room})(?::)?(.*)".format(
         free_member_room="[0-9]+",
         free_mirror_room="[0-9]+"))