#NEWLINE# def test_let_calls_function_immediately( self ) : #NEWLINE# #INDENT# called = [ False ] #NEWLINE# def func( x ) : #NEWLINE# #INDENT# called [ 0 ] = True #NEWLINE# return x #NEWLINE# #UNINDENT# Observable . empty ( ) . let_bind ( func ) #NEWLINE# assert called [ 0 ]