Small fix in __lt__ and __gt__

README.md

@@ -72,8 +72,6 @@ print(a)
 foo@bar:~$ python test.py
 0.1.0
 1.0.0-pre+build.1
-2.0.0-pre+build.1
-2.0.0-dev+build.1
 ```
 
 ### Manipulate specific parts

csemver/csemver.py

@@ -32,11 +32,6 @@
 					   """, re.VERBOSE)
 _num = re.compile(r"^[1-9][0-9]*$")
 
-if not hasattr(__builtins__, 'cmp'):
-    def cmp(a, b):
-        return (a > b) - (a < b)
-
-
 class csemver:
 	""" Representation of an semantic software version """
 
@@ -53,16 +48,6 @@ def __init__(self, version = "0.1.0"):
 		'!=': self.__ne__
 		}
 
-	def _build(self, val):
-		if _valid_ident.match(val) is not None:
-			self._version['build'] = val;
-		else:
-			raise ValueError("Not a valid build tag!")
-
-	def _prerelease(self,val):
-		newstr = sv.format_version(self._version['major'],self._version['minor'],self._version['patch'],val,self._version['build']);
-		self._version = sv.parse(newstr);
-
 	@deprecated
 	def setNumber(self,val):
 		self._version = self._parse(val)
@@ -137,7 +122,10 @@ def __setitem__(self, key, val):
 				raise ValueError("%s must be a number or a string!" % key)
 			self._version[key] = int(val);
 		else:
-			if not isinstance(val, str):
+			if val is None:
+				self._version[key] = None
+				return
+			if not isinstance(val,str):
 				raise TypeError("%s must be a string" % key)
 			if _valid_ident.match(val) is None:
 				raise ValueError("%s must be a valid semver identifier!" % key)
@@ -189,7 +177,7 @@ def __gt__(self, value):
 		i,v = next(mmp)
 		if (i is None) and (v is not None):
 			return True
-		elif (i is not None) and (v is None):
+		elif i is None or v is None:
 			return False
 
 		# Check prerelease identfiers
@@ -224,7 +212,7 @@ def __lt__(self, value):
 		i,v = next(mmp)
 		if (i is not None) and (v is None):
 			return True
-		elif (i is None) and (v is not None):
+		elif i is None or v is None:
 			return False
 
 		# Check prerelease identfiers