diff --git a/dot2tex/__init__.py b/dot2tex/__init__.py
index 61ab088..1ed59f7 100644
--- a/dot2tex/__init__.py
+++ b/dot2tex/__init__.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 """Convert graphviz graphs to LaTeX-friendly formats
 
 Various tools for converting graphs generated by the graphviz library
diff --git a/dot2tex/base.py b/dot2tex/base.py
index 051f473..6fafca3 100644
--- a/dot2tex/base.py
+++ b/dot2tex/base.py
@@ -216,7 +216,7 @@ def get_drawobj_lblstyle(drawobj, extra_styles=None):
     ])) or None
 
 
-class DotConvBase(object):
+class DotConvBase:
     """Dot2TeX converter base"""
 
     def __init__(self, options=None):
@@ -1024,7 +1024,7 @@ def process(self):
             s += "\end{preview}%\n"
         with open(self.tempfilename, 'w') as f:
             f.write(self.template.replace('<<preproccode>>', s))
-        with open(self.tempfilename, 'r') as f:
+        with open(self.tempfilename) as f:
             s = f.read()
         log.debug('Code written to %s\n' % self.tempfilename + s)
         self.parse_log_file()
@@ -1063,7 +1063,7 @@ def parse_log_file(self):
         p.kill()
         p.wait()
 
-        with open(logfilename, 'r') as f:
+        with open(logfilename) as f:
             logdata = f.read()
         log.debug('Logfile from LaTeX run: \n' + logdata)
         os.chdir(tmpdir)
diff --git a/dot2tex/dot2tex.py b/dot2tex/dot2tex.py
index 2a28674..1fc76c1 100644
--- a/dot2tex/dot2tex.py
+++ b/dot2tex/dot2tex.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """Convert graphviz graphs to LaTeX-friendly formats
 
 Various tools for converting graphs generated by the graphviz library
@@ -251,7 +250,7 @@ def print_version_info():
 
 
 def load_dot_file(filename):
-    with open(filename, 'r') as f:
+    with open(filename) as f:
         dotdata = f.readlines()
     log.info('Data read from %s' % filename)
     return dotdata
diff --git a/dot2tex/dotparsing.py b/dot2tex/dotparsing.py
index c039eb2..8dec0a9 100644
--- a/dot2tex/dotparsing.py
+++ b/dot2tex/dotparsing.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """Graphviz dot language parser.
 
 This parser is derived from the the parser distributed with the pydot module.
@@ -65,10 +64,7 @@ def needs_quotes(s):
             ##                if not res:
             ##                    res = id_re_with_port.match(s)
 
-    if not res:
-        return True
-
-    return False
+    return not res
 
 
 def quote_if_necessary(s):
@@ -84,9 +80,8 @@ def quote_if_necessary(s):
 
 def flatten(lst):
     for elem in lst:
-        if type(elem) in (tuple, list):
-            for i in flatten(elem):
-                yield i
+        if isinstance(elem, (tuple, list)):
+            yield from flatten(elem)
         else:
             yield elem
 
@@ -121,7 +116,7 @@ def nsplit(seq, n=2):
     >>> nsplit('aabbcc',n=4)
     [('a', 'a', 'b', 'b')]
     """
-    return [xy for xy in zip(*[iter(seq)] * n)]
+    return list(zip(*[iter(seq)] * n))
 
 
 # The following function is from the pydot project
@@ -286,7 +281,7 @@ def find_graphviz():
 SET_GRAPH_ATTR = 'set_graph_attr'
 
 
-class DotDataParser(object):
+class DotDataParser:
     """Container class for parsing Graphviz dot data"""
 
     def __init__(self):
@@ -426,8 +421,8 @@ def parse_html(s, loc, toks):
         closer = '>'
         try:
             html_text = pyparsing.nestedExpr(opener, closer,
-                                             ((CharsNotIn(
-                                                     opener + closer).setParseAction(lambda t: t[0]))
+                                             (CharsNotIn(
+                                                     opener + closer).setParseAction(lambda t: t[0])
                                               )).setParseAction(parse_html)
         except:
             log.debug('nestedExpr not available.')
@@ -449,11 +444,11 @@ def parse_html(s, loc, toks):
 
         port_angle = (at + ID).setName("port_angle")
 
-        port_location = ((OneOrMore(Group(colon + ID)) |
-                          Group(colon + lparen + ID + comma + ID + rparen))).setName("port_location")
+        port_location = (OneOrMore(Group(colon + ID)) |
+                          Group(colon + lparen + ID + comma + ID + rparen)).setName("port_location")
 
-        port = Combine((Group(port_location + Optional(port_angle)) |
-                        Group(port_angle + Optional(port_location)))).setName("port")
+        port = Combine(Group(port_location + Optional(port_angle)) |
+                        Group(port_angle + Optional(port_location))).setName("port")
 
         node_id = (ID + Optional(port))
         a_list = OneOrMore(ID + Optional(equals + righthand_id) +
@@ -627,7 +622,7 @@ def parse_dot_data_debug(self, data):
             return None
 
 
-class DotDefaultAttr(object):
+class DotDefaultAttr:
     def __init__(self, element_type, **kwds):
         self.element_type = element_type
         self.attr = kwds
@@ -647,7 +642,7 @@ class DotParsingException(Exception):
     """Base class for dotparsing exceptions."""
 
 
-class DotNode(object):
+class DotNode:
     """Class representing a DOT node"""
 
     def __init__(self, name, **kwds):
@@ -693,7 +688,7 @@ def __getattr__(self, name):
             raise AttributeError
 
 
-class DotGraph(object):
+class DotGraph:
     """Class representing a DOT graph"""
 
     def __init__(self, name='G', strict=True, directed=False, **kwds):
@@ -1003,7 +998,7 @@ def __str__(self):
                 'subgraph', self.get_name(), subgraphstr, attrstr, nodestr, edgestr, padding)
 
 
-class DotEdge(object):
+class DotEdge:
     """Class representing a DOT edge"""
 
     def __init__(self, src, dst, directed=False, src_port="", dst_port="", **kwds):
diff --git a/dot2tex/pgfformat.py b/dot2tex/pgfformat.py
index 83c77a5..c264bb8 100644
--- a/dot2tex/pgfformat.py
+++ b/dot2tex/pgfformat.py
@@ -343,9 +343,8 @@ def draw_text(self, drawop, style=None):
     def draw_bezier(self, drawop, style=None):
         s = ""
         c, points = drawop
-        pp = []
-        for point in points:
-            pp.append("(%sbp,%sbp)" % (smart_float(point[0]), smart_float(point[1])))
+        pp = ["(%sbp,%sbp)" % (smart_float(point[0]), smart_float(point[1]))
+              for point in points]
 
         pstrs = ["%s .. controls %s and %s " % p for p in nsplit(pp, 3)]
         stylestr = ''
diff --git a/dot2tex/pstricksformat.py b/dot2tex/pstricksformat.py
index 45e9678..37302e1 100644
--- a/dot2tex/pstricksformat.py
+++ b/dot2tex/pstricksformat.py
@@ -123,9 +123,8 @@ def draw_polyline(self, drawop, style=None):
 
     def draw_bezier(self, drawop, style=None):
         op, points = drawop
-        pp = []
-        for point in points:
-            pp.append("(%sbp,%sbp)" % (smart_float(point[0]), smart_float(point[1])))
+        pp = ["(%sbp,%sbp)" % (smart_float(point[0]), smart_float(point[1]))
+              for point in points]
 
         arrowstyle = ""
         return "  \psbezier{%s}%s\n" % (arrowstyle, "".join(pp))
@@ -465,4 +464,4 @@ def start_node(self, node):
         return ""
 
     def end_node(self, node):
-        return ""
\ No newline at end of file
+        return ""
diff --git a/dot2tex/utils.py b/dot2tex/utils.py
index 09739c7..e776f2e 100644
--- a/dot2tex/utils.py
+++ b/dot2tex/utils.py
@@ -50,7 +50,7 @@ def nsplit(seq, n=2):
     >>> nsplit('aabbcc',n=4)
     [('a', 'a', 'b', 'b')]
     """
-    return [xy for xy in zip(*[iter(seq)] * n)]
+    return list(zip(*[iter(seq)] * n))
 
 
 def chunks(s, cl):
@@ -101,7 +101,7 @@ def is_multiline_label(drawobject):
     return any(x in label for x in [r"\n", r"\l", r"\r"])
 
 
-class EndOfGraphElement(object):
+class EndOfGraphElement:
     def __init__(self):
         pass
 
@@ -124,4 +124,4 @@ def get_all_graph_elements(graph, l=None):
     if outer:
         return l
     else:
-        l.append(EndOfGraphElement())
\ No newline at end of file
+        l.append(EndOfGraphElement())