Made a lot of changes to reduce the eventual difference between the Python 2 version and the Python 3 version.

1 files changed, 2 insertions, 1 deletions

diff --git a/bs4/builder/_lxml.py b/bs4/builder/_lxml.py
index 57798f6..07b2032 100644
--- a/bs4/builder/_lxml.py
+++ b/bs4/builder/_lxml.py
@@ -3,6 +3,7 @@ __all__ = [
     'LXMLTreeBuilder',
     ]
 
+import collections
 from lxml import etree
 from bs4.element import Comment, Doctype
 from bs4.builder import (
@@ -36,7 +37,7 @@ class LXMLTreeBuilderForXML(TreeBuilder):
         if parser is None:
             # Use the default parser.
             parser = self.default_parser
-        if callable(parser):
+        if isinstance(parser, collections.Callable):
             # Instantiate the parser with default arguments
             parser = parser(target=self, strip_cdata=False)
         self.parser = parser