diff --git a/src/datafile.py b/src/datafile.py
--- a/src/datafile.py
+++ b/src/datafile.py
@@ -1,28 +1,28 @@
 from hashtree import HashTree
 
 
-BLOCK_SIZE=HashTree.BLOCK_SIZE
+BLOCK_SIZE = HashTree.BLOCK_SIZE
 
 
 class DataFile:
-	def __init__(self,fileHandle):
-		self._lastIndex=0
-		self._f=fileHandle
+	def __init__(self, fileHandle):
+		self._lastIndex = 0
+		self._f = fileHandle
 
 	@staticmethod
-	def open(filename,mode="rb"):
-		return DataFile(open(filename,mode=mode))
+	def open(filename, mode="rb"):
+		return DataFile(open(filename, mode=mode))
 
-	def writeAt(self,i,blockData):
+	def writeAt(self, i, blockData):
 		if i!=self._lastIndex+1:
 			self._f.seek(i*BLOCK_SIZE)
 		self._f.write(blockData)
-		self._lastIndex=i
+		self._lastIndex = i
 
-	def readFrom(self,i,byteCount=BLOCK_SIZE):
+	def readFrom(self, i, byteCount=BLOCK_SIZE):
 		if i!=self._lastIndex+1:
 			self._f.seek(i*BLOCK_SIZE)
-		self._lastIndex=i
+		self._lastIndex = i
 		return self._f.read(byteCount)
 
 	def close(self):