When we instantiate a turtle object, we can draw a circle. I wonder about the radius parameter of the circle() method.

import turtle
myTurtle = turtle.Turtle()
myTurtle.circle(50)

What is the unit of measurement of this parameter?

Does the radius equal to 50 pixels or 50 inches?

the documentation for turtle.setup indicates that size parameters, if expressed as integers, are pixels, if expressed as floats, are fractions of the screen.