added xml validation

xml_reader.py

@@ -1,15 +1,30 @@
-import xml.etree.ElementTree as ET
-
+from lxml import etree
 class Xml_reader:
     """ reader for the XML configuration """
 
-    def __init__(self, path):
+    def __init__(self, xml_path, xsd_path):
         """inits the reader
 
         Args:
             path (string): path to the XML config file
         """
-        self.root = ET.parse(path).getroot()
+        #check the XML for validity using the XSD file
+        if not self.validate(xml_path,xsd_path):
+            raise SyntaxError('the XML config file has an invalid syntax')
+        self.root = etree.parse(xml_path).getroot()
+
+    def validate(self, xml_path:str, xsd_path: str) -> bool:
+        """validates a xml by using a xsd file
+
+        Args:
+            xml_path (str): the path to the xml file
+            xsd_path (str): the path to the xsd file
+
+        Returns:
+            bool: result of the validation
+        """
+        xml_schema = etree.XMLSchema(etree.parse(xsd_path))
+        return xml_schema.validate(etree.parse(xml_path))
 
     def get_device_names(self):
         """returns the names of all devices in the config