<p>I am using <code>pyexcelerator</code> Python module to generate Excel files. 
I want to apply bold style to part of cell text, but not to the whole cell.
How to do it?</p>

This is an example from Excel documentation:
```
```
With Worksheets("Sheet1").Range("B1")
    .Value = "New Title"
    .Characters(5, 5).Font.Bold = True
End With
```
```
So the Characters property of the cell you want to manipulate is the answer to your question. It's used as Characters(
start
,
length
).
PS: I've never used the module in question, but I've used Excel COM automation in python scripts. The Characters property is available using win32com.