Adding graph points and formating

[BashBedlam]

FYI x1 is not the same as x[1] or x[increment]. x1 is a variable name and x[1] is a reference to a list element. I've added two lists to the get_nums () method so that you can reference your variables as list elements.
Personally, I would reconsider the use your class variable --hiddenVar.

class Input_Points:
 
    __hiddenVar = 0 #hidden variable, to be used only within this class for increments
 
 
    # constructor, arguement receives 4 instance attributes
    #def __init__(self,x1, y1, x2, y2, __hiddenVar):
    def __init__(self, x1, y1, x2, y2):
        self.x1 = x1
        self.y1 = y1
        self.x2 = x2
        self.y2 = y2
        # self.__hiddenVar = __hiddenVar
 
    """Get integers from user"""
    def set_nums(self):
        self.x1 = int(input('enter x1: '))
        self.y1 = int(input('enter y1: '))
        self.x2 = int(input('enter x2: '))
        self.y2 = int(input('enter y2: '))
 
    """
     #code below works
        # format the results, using string formatting
    def get_nums(self):
        return print("point 1 = ({},{})".format(self.x1, self.y1))
    """
 
 
 
    # format the results, using string formatting
    def get_nums(self, increment):
        x = [self.x1, self.x2]
        y = [self.y1, self.y2]
        while (increment < 2):
            #print("point", increment, "= ({},{})".format(self.x1, self.y1))
            print("point", increment, "= ({},{})".format(x[increment], y[increment]))
            increment += 1
 
        #return print("point = ", increment, "{},{}".format(self.x1, self.y1))
 
# Class: Input_Points
w1 = Input_Points("","","","") # no default parameters
w1.set_nums()
#w1.get_nums()
 
w1.get_nums(w1._Input_Points__hiddenVar)