Undefined name: Set() --> set()

__Set()__ is an _undefined name_ in this context but __set()__ is used elsewhere in this class.

[flake8](http://flake8.pycqa.org) testing of https://github.com/pyparsing/pyparsing on Python 3.7.1

$ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__
```
./examples/searchParserAppDemo.py:15:18: F821 undefined name 'Set'
        result = Set()
                 ^
1    F821 undefined name 'Set'
1
```

1 files changed, 2 insertions, 2 deletions

diff --git a/examples/searchParserAppDemo.py b/examples/searchParserAppDemo.py
index 0532c1c..021428d 100644
--- a/examples/searchParserAppDemo.py
+++ b/examples/searchParserAppDemo.py
@@ -12,7 +12,7 @@ class FruitSearchParser(SearchQueryParser):
         return { p for p in products if p.startswith(word[:-1]) }

 

     def GetQuotes(self, search_string, tmp_result):

-        result = Set()

+        result = set()

         # I have no idea how to use this feature...

         return result

 

@@ -31,4 +31,4 @@ tests = """\
 for t in tests:

     print(t.strip())

     print(parser.Parse(t))

-    print('')
\ No newline at end of file
+    print('')