diff --git a/src/diana/sgfParser/node.py b/src/diana/sgfParser/node.py
--- a/src/diana/sgfParser/node.py
+++ b/src/diana/sgfParser/node.py
@@ -7,91 +7,97 @@ from .property import Property, GAME_INF
 
 class Node:
 	def __init__(self):
-		self.properties=dict()
-		self.parent=None
-		self.children=[]
+		self.properties = dict()
+		self.parent = None
+		self.children = []
 
 	@staticmethod
-	def fits(s,i):
-		return i<len(s) and s[i]==";"
+	def fits(s, i):
+		return i < len(s) and s[i] == ";"
 
 	@staticmethod
-	def create(s,start):
-		assert Node.fits(s,start)
-		res=Node()
+	def create(s, start):
+		assert Node.fits(s, start)
+		res = Node()
 
-		i=skipWhitespace(s,start+1)
-		while Property.fits(s,i):
-			i,x=Property.create(s,i)
+		i = skipWhitespace(s, start+1)
+		while Property.fits(s, i):
+			(i, x) = Property.create(s, i)
 			if x.name in res.properties:
-				log.warning(ParserWarning('duplicate "{0}" property in a node. second value ignored'.format(x.name),s,i))
+				log.warning(ParserWarning('duplicate "{0}" property in a node. second value ignored'.format(x.name), s, i))
 			else:
-				res.properties[x.name]=x
-			i=skipWhitespace(s,i)
-		return (i,res)
+				res.properties[x.name] = x
+			i = skipWhitespace(s, i)
+		return (i, res)
 
 	def listGINodes(self):
-		if self.isGINode(): yield self
-		empty=not self.isGINode()
+		if self.isGINode():
+			yield self
+		empty = not self.isGINode()
 
-		node=self
+		node = self
 		while node.parent:
-			node=node.parent
+			node = node.parent
 			if node.isGINode():
-				empty=False
+				empty = False
 				yield node
 
-		queue=deque(self.children)
-		while len(queue)>0:
-			node=queue.popleft()
+		queue = deque(self.children)
+		while len(queue) > 0:
+			node = queue.popleft()
 			if node.isGINode():
-				empty=False
+				empty = False
 				yield node
 			queue.extend(node.children)
-		if empty: yield self # always yield at least self, can work as GINode as well as any other
+		if empty:
+			yield self  # always yield at least self, can work as GINode as well as any other
 
 	def isGINode(self):
-		return any(prop.type==GAME_INFO for prop in self.properties.values())
+		return any(prop.type == GAME_INFO for prop in self.properties.values())
 
-	def setProp(self,name,value):
-		self.properties[name]=value
-		# zkontrolovat typ value
+	def setProp(self, name, value):
+		self.properties[name] = value
+		# check value type
 
-	def setChildren(self,children):
-		self.children=children
-		for child in children: child.parent=self
+	def setChildren(self, children):
+		self.children = children
+		for child in children:
+			child.parent = self
 
-	def addChild(self,node):
-		if node in self.children: return node
-		node.parent=self
+	def addChild(self, node):
+		if node in self.children:
+			return node
+		node.parent = self
 		self.children.append(node)
 		return node
 
-	def removeChild(self,node):
+	def removeChild(self, node):
 		if node not in self.children:
 			return None
 		del self.children[self.children.index(node)]
-		node.parent=None
+		node.parent = None
 		return node
 
-	def removeChildAt(self,i):
-		if -len(self.children)<i<len(self.children):
-			res=self.children[i]
+	def removeChildAt(self, i):
+		if -len(self.children) < i < len(self.children):
+			res = self.children[i]
 			del self.children[i]
-			res.parent=None
+			res.parent = None
 			return res
 		return None
 
 	## Create a copy of the Node, with the same parent and deep copied properties, no copied children.
 	def copy(self):
-		res=Node()
-		res.properties={k: v.copy() for (k,v) in self.properties.items()}
-		res.parent=self.parent
+		res = Node()
+		res.properties = {k: v.copy() for (k, v) in self.properties.items()}
+		res.parent = self.parent
 		return res
 
-	def getProp(self,name,default=None):
-		if name in self.properties: return self.properties[name].value
-		else: return default
+	def getProp(self, name, default=None):
+		if name in self.properties:
+			return self.properties[name].value
+		else:
+			return default
 
 	## Returns textual representation of the Node itself, but disregards its children.
 	def __str__(self):
@@ -99,22 +105,23 @@ class Node:
 
 	def export(self):
 		# there is a beautiful recursive solution, which this stack is too narrow to contain
-		stack=[(self,1,1)]
-		output=[]
+		stack = [(self, 1, 1)]
+		output = []
 
-		while len(stack)>0:
-			node,left,right=stack.pop()
-			if left>0: output.append("("*left)
+		while len(stack) > 0:
+			(node, left, right) = stack.pop()
+			if left > 0:
+				output.append("("*left)
 			output.append(str(node)+"\n")
 
-			childCount=len(node.children)
-			if childCount==0: # a leaf
+			childCount = len(node.children)
+			if childCount == 0:  # a leaf
 				output.append(")"*right+"\n")
-			elif childCount==1: # a line
-				stack.append((node.children[0],0,right))
-			else: # a branching node
+			elif childCount == 1:  # a line
+				stack.append((node.children[0], 0, right))
+			else:  # a branching node
 				# first child pops first, last child closes parent's parentheses
-				children=zip(node.children,[1]*childCount,[1]*(childCount-1)+[1+right])
-				stack.extend(reversed(children))
+				children = zip(node.children, [1]*childCount, [1]*(childCount-1)+[1+right])
+				stack.extend(reversed(list(children)))
 
 		return "".join(output)