Declaring a supertype as variable type

Sometimes the inferred type is a subtype (subclass) of the desiredtype. The type inference uses the first assignment to infer the typeof a name (assume here that Shape is the base class of bothCircle and Triangle):

shape = Circle()    # Infer shape to be Circle
...
shape = Triangle()  # Type error: Triangle is not a Circle

You can just give an explicit type for the variable in cases such theabove example:

shape = Circle() # type: Shape   # The variable s can be any Shape,
                                 # not just Circle
...
shape = Triangle()               # OK