The Indentation manager, accessible from the Tools menu, can be used to inspect and change indentation style in source files. It has two parts: (1) The indentation report, and (2) the indentation converter.
A report on the nature of existing indentation found in your source file is given above the horizontal divider. This includes the number of spaces-only, tabs-only, and mixed tabs-and-space indents found, information about whether indentation in the file may be problematic to the Python interpreter, and the tab and indent size computed for that file. The manager also provides information about where the computed tab and indent size value come from (for example, an empty file results in use of the defaults configured in preferences).
Conversion options for your file are given below the horizontal divider. The three tabs are used to select the type of conversion desired, and each tab contains information about the availability and action of that conversion, and a button to start the conversion. In some of the conversion options, the indent size field shown in the indentation report is made editable, to allow specification of the desired resulting indent size.
Once conversion is complete, the indentation manager updates to display the new status of the file, and action of any subsequent conversions.
Conversions can be undone be moving to the converted source file and selecting Undo from the Edit menu.