human
Solve the following python programming problem given the following code:
def connect_float_edit(client, prop, widget) : 
    '
    Connect widget.setText and client.prop
    Also pretty-print the number

    client.prop should be a callback property
    ' 
    v = QtGui.QDoubleValidator (None) 
    v.setDecimals (4) 
    widget.setValidator (v) 
    def update_prop() : 
        val = widget.text () 
        try : 
            setattr (client, prop, float (val)) 
except ValueError : 
            setattr (client, prop, 0) 
def update_widget(val) : 
        if (val is None) : 
            val = 0.0 
widget.setText (pretty_number (val)) 
add_callback (client, v, update_widget) 
    widget.editingFinished.connect (update_prop) 
    update_widget (getattr (client, prop)) 

    
    

    Fix the buggy line: add_callback (client, v, update_widget)
assistant
#Here is Python program to fix the buggy line: add_callback (client, v, update_widget)
.

add_callback (client, prop, update_widget)