diff --git a/src/pslint.py b/src/pslint.py
index 37bf4df..7582ae2 100755
--- a/src/pslint.py
+++ b/src/pslint.py
@@ -31,155 +31,155 @@ warnings = 0
 errors = 0
 
 def warning(msg):
-  global warnings, line, nline
-  print('%d: warning: %s: \'%s\'' % (nline, msg, line))
-  warnings += 1
+	global warnings, line, nline
+	print('%d: warning: %s: \'%s\'' % (nline, msg, line))
+	warnings += 1
 
 def error(msg):
-  global errors, line, nline
-  print('%d: error: %s: \'%s\'' % (nline, msg, line))
-  errors += 1
+	global errors, line, nline
+	print('%d: error: %s: \'%s\'' % (nline, msg, line))
+	errors += 1
 
 def lint_psl(infile):
-  """Parses PSL file and extract strings and return code"""
-  global line, nline
+	"""Parses PSL file and extract strings and return code"""
+	global line, nline
 
-  PSL_FLAG_EXCEPTION = (1<<0)
-  PSL_FLAG_WILDCARD = (1<<1)
-  PSL_FLAG_ICANN = (1<<2) # entry of ICANN section
-  PSL_FLAG_PRIVATE = (1<<3) # entry of PRIVATE section
-  PSL_FLAG_PLAIN = (1<<4) #just used for PSL syntax checking
+	PSL_FLAG_EXCEPTION = (1<<0)
+	PSL_FLAG_WILDCARD = (1<<1)
+	PSL_FLAG_ICANN = (1<<2) # entry of ICANN section
+	PSL_FLAG_PRIVATE = (1<<3) # entry of PRIVATE section
+	PSL_FLAG_PLAIN = (1<<4) #just used for PSL syntax checking
 
-  psl = {}
-  section = 0
+	psl = {}
+	section = 0
 
-  lines = [line.strip('\r\n') for line in infile]
+	lines = [line.strip('\r\n') for line in infile]
 
-  for line in lines:
-    nline += 1
+	for line in lines:
+		nline += 1
 
-	 # check for leadind/trailing whitespace
-    stripped = line.strip()
-    if stripped != line:
-      warning('Leading/Trailing whitespace')
-    line = stripped
+		# check for leadind/trailing whitespace
+		stripped = line.strip()
+		if stripped != line:
+			warning('Leading/Trailing whitespace')
+		line = stripped
 
-    # empty line
-    if not line:
-      continue
+		# empty line
+		if not line:
+			continue
 
-    # check for section begin/end
-    if line[0:2] == "//":
-      if section == 0:
-        if line == "// ===BEGIN ICANN DOMAINS===":
-          section = PSL_FLAG_ICANN
-        elif line == "// ===BEGIN PRIVATE DOMAINS===":
-          section = PSL_FLAG_PRIVATE
-        elif line[3:8] == "===BEGIN":
-          error('Unexpected begin of unknown section')
-        elif line[3:6] == "===END":
-          error('End of section without previous begin')
-      elif section == PSL_FLAG_ICANN:
-        if line == "// ===END ICANN DOMAINS===":
-          section = 0
-        elif line[3:8] == "===BEGIN":
-          error('Unexpected begin of section: ')
-        elif line[3:6] == "===END":
-          error('Unexpected end of section')
-      elif section == PSL_FLAG_PRIVATE:
-        if line == "// ===END ICANN DOMAINS===":
-          section = 0
-        elif line[3:8] == "===BEGIN":
-          error('Unexpected begin of section')
-        elif line[3:6] == "===END":
-          error('Unexpected end of section')
+		# check for section begin/end
+		if line[0:2] == "//":
+			if section == 0:
+				if line == "// ===BEGIN ICANN DOMAINS===":
+					section = PSL_FLAG_ICANN
+				elif line == "// ===BEGIN PRIVATE DOMAINS===":
+					section = PSL_FLAG_PRIVATE
+				elif line[3:8] == "===BEGIN":
+					error('Unexpected begin of unknown section')
+				elif line[3:6] == "===END":
+					error('End of section without previous begin')
+			elif section == PSL_FLAG_ICANN:
+				if line == "// ===END ICANN DOMAINS===":
+					section = 0
+				elif line[3:8] == "===BEGIN":
+					error('Unexpected begin of section: ')
+				elif line[3:6] == "===END":
+					error('Unexpected end of section')
+			elif section == PSL_FLAG_PRIVATE:
+				if line == "// ===END ICANN DOMAINS===":
+					section = 0
+				elif line[3:8] == "===BEGIN":
+					error('Unexpected begin of section')
+				elif line[3:6] == "===END":
+					error('Unexpected end of section')
 
-      continue # processing of comments ends here
+			continue # processing of comments ends here
 
-    # No rule must be outside of a section
-    if section == 0:
-      error('Rule outside of section')
+		# No rule must be outside of a section
+		if section == 0:
+			error('Rule outside of section')
 
-    # decode UTF-8 input into unicode, needed only for python 2.x
-    if sys.version_info[0] < 3:
-      line = line.decode('utf-8')
+		# decode UTF-8 input into unicode, needed only for python 2.x
+		if sys.version_info[0] < 3:
+			line = line.decode('utf-8')
 
 	 # each rule must be lowercase (or more exactly: not uppercase and not titlecase)
-    if line != line.lower():
-      error('Rule must be lowercase')
+		if line != line.lower():
+			error('Rule must be lowercase')
 
-    # strip leading wildcards
-    flags = 0
-    # while line[0:2] == '*.':
-    if line[0:2] == '*.':
-      flags = PSL_FLAG_WILDCARD | PSL_FLAG_PLAIN | section
-      line = line[2:]
+		# strip leading wildcards
+		flags = 0
+		# while line[0:2] == '*.':
+		if line[0:2] == '*.':
+			flags = PSL_FLAG_WILDCARD | PSL_FLAG_PLAIN | section
+			line = line[2:]
 
-    if line[0] == '!':
-      flags = PSL_FLAG_EXCEPTION | section
-      line = line[1:]
+		if line[0] == '!':
+			flags = PSL_FLAG_EXCEPTION | section
+			line = line[1:]
 
-    # wildcard and exception must not combine
-    if flags & PSL_FLAG_WILDCARD and flags & PSL_FLAG_EXCEPTION:
-      error('Combination of wildcard and exception')
+		# wildcard and exception must not combine
+		if flags & PSL_FLAG_WILDCARD and flags & PSL_FLAG_EXCEPTION:
+			error('Combination of wildcard and exception')
 
-    labels = line.split('.')
+		labels = line.split('.')
 
-    for label in labels:
-      if not label:
-         error('Leading/trailing or multiple dot')
-         continue
+		for label in labels:
+			if not label:
+				 error('Leading/trailing or multiple dot')
+				 continue
 
-      if label[0:4] == 'xn--':
-         error('Punycode found')
-         continue
+			if label[0:4] == 'xn--':
+				 error('Punycode found')
+				 continue
 
-      if '--' in label:
-         error('Double minus found')
-         continue
+			if '--' in label:
+				 error('Double minus found')
+				 continue
 
-      # allowed are a-z,0-9,- and unicode >= 128 (maybe that can be finetuned a bit !?)
-      for c in label:
-        if not c.isalnum() and c != '-' and ord(c) < 128:
-          error('Illegal character')
-          break
+			# allowed are a-z,0-9,- and unicode >= 128 (maybe that can be finetuned a bit !?)
+			for c in label:
+				if not c.isalnum() and c != '-' and ord(c) < 128:
+					error('Illegal character')
+					break
 
-    if line in psl:
-      """Found existing entry:
-         Combination of exception and plain rule is ambiguous
-           !foo.bar
-            foo.bar
+		if line in psl:
+			"""Found existing entry:
+				 Combination of exception and plain rule is ambiguous
+					 !foo.bar
+						foo.bar
 
-         Allowed:
-           !foo.bar + *.foo.bar
-            foo.bar + *.foo.bar
-      """
-      error('Found doublette/ambiguity (previous line was %d)' % psl[line])
-      continue
+				 Allowed:
+					 !foo.bar + *.foo.bar
+						foo.bar + *.foo.bar
+			"""
+			error('Found doublette/ambiguity (previous line was %d)' % psl[line])
+			continue
 
-    psl[line] = nline
+		psl[line] = nline
 
 
 def usage():
-  """Prints the usage"""
-  print('usage: %s PSLfile' % sys.argv[0])
-  print('or     %s -        # To read PSL from STDIN' % sys.argv[0])
-  exit(1)
+	"""Prints the usage"""
+	print('usage: %s PSLfile' % sys.argv[0])
+	print('or     %s -        # To read PSL from STDIN' % sys.argv[0])
+	exit(1)
 
 
 def main():
-  """Check syntax of a PSL file"""
-  if len(sys.argv) < 2:
-    usage()
+	"""Check syntax of a PSL file"""
+	if len(sys.argv) < 2:
+		usage()
 
-  if sys.argv[-1] == '-':
-    lint_psl(sys.stdin)
-  else:
-    with open(sys.argv[-1], 'r') as infile:
-      lint_psl(infile)
+	if sys.argv[-1] == '-':
+		lint_psl(sys.stdin)
+	else:
+		with open(sys.argv[-1], 'r') as infile:
+			lint_psl(infile)
 
-  return errors != 0
+	return errors != 0
 
 
 if __name__ == '__main__':
-  sys.exit(main())
+	sys.exit(main())