How to force ElementTree to look in a specific directory for xml files?

I have been trying to get ElementTree(ET) to look for xml files in a specific directory which the user will point to, however I found out that ET is only searching for that xml file in the directory of the script itself. How can I force ET to look in the right directory, and why is it ignoring the one that is passed down to it?

The code is split into two different scripts.

main.py:

#This script is mainly a tkinter script with buttons/entries. One button takes the given directory and passes it over to a function that launches the second script/function. Including this here to better make sense of how the code will be working
.
.
def clicked(self):
    check_xml(self.directory)#the value that is stored from a different button

classes.py:

import os
import glob
import xml.etree.ElementTree as ET

def check_xml(x):
    tree = ET.parse('sample.xml')
    root = tree.getroot()

    print(tree)

The folder structure is as follows:
root/main folder(This is what 'self.directory' and 'x' will point to):

|--projectFolder
 |--subfolder
  |--anotherXML.xml
 |--sample.xml

Eventually I would go into the other xml's but right now I'm trying to work my way up(down?) by making sure the code works correctly and displays the information I want.

Why is it that 'x' gets ignored by the function, and instead only checks the directory that the code itself is in only, and how can I get it to work correctly?

check if x contains correct file path along with the file name "sample.xml"
in it.

For Example:

x = 'C:\\Users\\stdev\\Desktop\\am\\sample.xml'

and then just call x into ET.parse()

example:

tree = ET.parse(x)

hope this helps

def check_xml(x):
    tree = ET.parse('sample.xml')
    root = tree.getroot()

    print(tree)

The file sample.xml is a relative path, and is interpreted relative to the current working directory. You want an absolute path.

Assuming self.directory contains an absolute path to a directory where you want to find sample.xml, you can use os.path.join to get an absolute path to sample.xml.

Example:

def check_xml(x):
    tree = ET.parse(os.path.join(x, 'sample.xml'))
    root = tree.getroot()

    print(tree)