add sample Worksheet User Tree Access.py

Author: mynehc

1. Origin-Python Data Exchange/Worksheet User Tree Access.py

@@ -0,0 +1,20 @@
+'''
+This sample shows how to set values to worksheet tree nodes, and 
+then read out into a tree object. This is useful to save the metadata
+of a data file. See the blog:
+https://blog.originlab.com/accessing-metadata-using-python
+'''
+
+import originpro as op
+
+# Create a new worksheet and set worksheet tree values.
+wks = op.new_sheet()
+wks.set_str("tree.data.name", "Larry")
+wks.set_int("tree.data.age", 37)
+wks.set_float("tree.data.mean", 23.56)
+
+# Save the worksheet tree values to a tree object and print out the values.
+trWks = wks.usertree
+trData = trWks.find('data')
+for child in trData:
+    print(f'{child.tag} = {child.text}')