fix for python3.11

gerber/common.py

@@ -36,7 +36,7 @@ def read(filename):
         CncFile object representing the file, either GerberFile, ExcellonFile,
         or IPCNetlist. Returns None if file is not of the proper type.
     """
-    with open(filename, 'rU') as f:
+    with open(filename, 'r', newline=None) as f:
         data = f.read()
     return loads(data, filename)
 

gerber/excellon.py

@@ -54,7 +54,7 @@ def read(filename):
 
     """
     # File object should use settings from source file by default.
-    with open(filename, 'rU') as f:
+    with open(filename, 'r', newline=None) as f:
         data = f.read()
     settings = FileSettings(**detect_excellon_format(data))
     return ExcellonParser(settings).parse(filename)
@@ -426,7 +426,7 @@ def hole_count(self):
         return len(self.hits)
 
     def parse(self, filename):
-        with open(filename, 'rU') as f:
+        with open(filename, 'r', newline=None) as f:
             data = f.read()
         return self.parse_raw(data, filename)
 
@@ -819,7 +819,7 @@ def detect_excellon_format(data=None, filename=None):
     if data is None and filename is None:
         raise ValueError('Either data or filename arguments must be provided')
     if data is None:
-        with open(filename, 'rU') as f:
+        with open(filename, 'r', newline=None) as f:
             data = f.read()
 
     # Check for obvious clues:

gerber/ipc356.py

@@ -163,7 +163,7 @@ def settings(self):
         return FileSettings(units=self.units, angle_units=self.angle_units)
 
     def parse(self, filename):
-        with open(filename, 'rU') as f:
+        with open(filename, 'r', newline=None) as f:
             data = f.read()
         return self.parse_raw(data, filename)