input: Write a python function to read an XML file and return its root element.
  assert isinstance(XmlReader('sample.xml').get_xml_data(), Element)
  assert XmlReader('sample.xml').get_xml_data().tag == 'root_tag_name'
  assert len(list(XmlReader('sample.xml').get_xml_data())) == expected_number_of_elements
output: import xml.etree.ElementTree as ET
  
  class XmlReader:
      def __init__(self, file_path):
          self.file_path = file_path
  
      def get_xml_data(self):
          tree = ET.parse(self.file_path)
          return tree.getroot()