human
I am working on the file "Python/11_Progress.ipynb".
The first task is:
We need to add a command to display the progress reported by the ProcessObject::GetProgress method during the sitkProgressEvent. This involves three components:

Events
ProcessObject's methods
Commands

We'll look at some examples after a brief explanation of these components.
Events
The avaiable events to observed are defined in a namespace enumeration.
<table>
 <tr><td>sitkAnyEvent</td><td>Occurs for all event types.</td></tr>
 <tr><td>sitkAbortEvent</td><td>Occurs after the process has been aborted, but before exiting the Execute method.</td></tr>
 <tr><td>sitkDeleteEvent</td><td>Occurs when the underlying itk::ProcessObject is deleted.</td></tr>
 <tr><td>sitkEndEvent</td><td>Occurs at then end of normal processing.</td></tr>
 <tr><td>sitkIterationEvent</td><td>Occurs with some algorithms that run for a fixed or undetermined number of iterations.</td></tr>
 <tr><td>sitkProgressEvent</td><td>Occurs when the progress changes in most process objects.</td></tr>
 <tr><td>sitkStartEvent</td><td>Occurs when then itk::ProcessObject is starting.</td></tr>
 <tr><td>sitkUserEvent</td><td>Other events may fall into this enumeration.</td></tr>
</table>

The convention of pre-fixing enums with "sitk" is continued, although it's getting a little crowded. 
C++ is more strongly typed than Python it allows for implicit conversion from an enum type to an int, but not from an int to an enum type. Care needs to be made to ensure the correct enum value is passed in Python.
ProcessObject's methods
To be able to interface with the ProcessObject during execution, the object-oriented interface must be used to access the method of the ProcessObject. While any constant member function can be called during a command call-back there are two common methods:

ProcessObject::GetProgress()
ProcessObject::Abort()

The methods are only valid during the Command while a process is being executed, or when the process is not in the Execute method.
Additionally it should be noted that follow methods can not be called during a command or from...
Can you write Python code for it?

=====
Write me a the Python code you requested?
assistant
#Here is the Python code you requested.

help(sitk.Command)

class MyCommand(sitk.Command):
    def __init__(self):
        # required
        super(MyCommand, self).__init__()

    def Execute(self):
        print("MyCommand::Execute Called")

cmd = MyCommand()
cmd.Execute()

help(sitk.PyCommand)

cmd = sitk.PyCommand()
cmd.SetCallbackPyCallable(lambda: print("PyCommand Called"))
cmd.Execute()