How to pass multiple operator properties via UI layout? Basically, I want to have a single operator which can do multiple things, based on some attributes values.

class MyPanel(bpy.types.Panel):
    # (...)
    layout = self.layout
    row = layout.row()
    row.operator("my.button", text="Button text")

class MY_BUTTON_OT_Button(bpy.types.Operator):
    bl_idname = "my.button"
    bl_description = "Button description"
    bl_label = "Button"
    foo = bpy.props.IntProperty()
    bar = bpy.props.BoolProperty()

    if bar:
        # Do something with foo
    else:
        # Do something else :P


I know how to set one attribute, like so:

    row.operator("my.button", text="Button text").foo=5


But what about multiple arguments?
I tried several things that didn't worked, like (e.g.):


With setattr():
row.operator("my.button", text="Button text").setattr(foo=5,bar=True)  
With a custom method setVal() in the operator class:
row.operator("my.button", text="Button text").setVal(foo=5,bar=True)


Maybe I must use a single EnumProperty? I hope to avoid this, so my question is:
Is it possible to pass multiple custom arguments to set attributes in an operator class? And if yes, how ?

Thanks for your help.
There may be other ways, but that's the easiest. Instead of using operator()'s return value (an OperatorProperties) right away, capture it in a variable, and assign them there:

props = row.operator("my.button", text="Button text")
props.foo = 5
props.bar = "Bar"
props.baz = True