Making a variable to work in another class without using a static class

Question

I am trying to call a variable or a StringVar from the class called GUI without calling the GUI as the object of the class Conversion. Here is an example of my code:

class GUI:
    def __init__(self,root):
        c = Conversion(measurements,measurements1,Text_Legnth_Left,Text_Length_Right)
        measurements = self.measurements
        measurements1 = self.measurements1
        Text_Length_Left = self.Text_Legnth_Left
        Text_Length_Right = self.Text_Length_Right

        self.notebook = ttk.Notebook(root)
        self.notebook.pack()

        self.length_frame = ttk.Frame(self.notebook)
        self.weight_frame = ttk.Frame(self.notebook)
        self.temperature_frame = ttk.Frame(self.notebook)

        self.notebook.add(self.length_frame, text = 'Length')

        #Combobox
        self.measurements = StringVar()
        self.Combobox_Length_Left = ttk.Combobox(self.length_frame, textvariable = self.measurements, values = ('mm', 'cm', 'inch', 'ft', 'yd', 'm', 'km', 'mi'), width = 10,state=['readonly'])
        self.Combobox_Length_Left.current(5)
        self.measurements.trace('w', c.update_length())
        self.Combobox_Length_Left.grid(row = 2, column = 0, padx = 5, pady = 5, sticky = E)

        self.measurements1 = StringVar()
        self.Combobox_Length_Right = ttk.Combobox(self.length_frame, textvariable = self.measurements1, value = ('mm', 'cm', 'inch', 'ft', 'yd', 'm', 'km', 'mi'), width = 10,state = ['readonly'])
        self.Combobox_Length_Right.current(5)
        self.measurements1.trace('w', c.self.update_length())
        self.Combobox_Length_Right.grid(row = 2, column = 2, padx = 5, pady = 5, sticky = E)

        #Labels
        self.Conversion = ttk.Label(self.length_frame, text = 'Conversion:').grid(row = 1, column = 0, padx = 5, pady = 5, sticky = W)
        self.Label_Blank = ttk.Label(self.length_frame, text = '').grid(row = 1, column = 1, padx = 5, pady = 5, sticky = E)
        self.Label_To2 = ttk.Label(self.length_frame, text = 'to').grid(row = 2, column = 1, padx = 5, pady = 5, sticky = E)
        self.Label_To = ttk.Label(self.length_frame, text = 'to').grid(row = 3, column = 1, padx = 5, pady = 5, sticky = E)

        #Entry Boxes
        self.Text_Length_Left = StringVar()
        self.Entry_Length_Left = ttk.Entry(self.length_frame, textvariable = self.Text_Length_Left,width = 13)
        self.Text_Length_Left.trace('w', self.update_length)
        self.Entry_Length_Left.grid(row = 3, column = 0, padx = 5, pady = 5)

        self.Text_Length_Right = StringVar()
        self.Entry_Length_Right = ttk.Entry(self.length_frame, textvariable = self.Text_Length_Right,width = 13, state='readonly')

And here is my other class:

class Conversion:
    def __init__(self,measurements,measurements1,Text_Legnth_Left,Text_Length_Right):
        g = GUI(measurements,measurements1,Text_Legnth_Left,Text_Length_Right)
        as_meter = dict(mm=0.001, cm=0.01, inch=0.0254,ft=0.3048, yd=0.9144, m=1.0,km=1000.0, mi=1609.344,)
        def update_length(self, *args,g):
            try:
                v = int(g.self.Text_Length_Left.get())
            except ValueError:
                g.self.Text_Length_Left.set('')
                g.self.Text_Length_Right.set('')
                return
            m = v * self.as_meter [g.self.measurements.get()]
            r = m/self.as_meter[g.self.measurements1.get()]
            g.self.Text_Length_Right.set("{:.5g}".format(r))

My attempt of calling the the variables such as measurements was c=Conversion(measurements) I know by doing class GUI(Conversion) will work and make it its object but I can't do it for specific reasons.

Thanks for any help really appreciate it!