--- a
+++ b/pathaia/patches/errors.py
@@ -0,0 +1,65 @@
+# coding: utf8
+"""
+A module to handle patchification errors.
+
+Enable catching of level and filter accesses.
+"""
+
+
+class Error(Exception):
+    """
+    Base of custom errors.
+
+    **********************
+    """
+
+    pass
+
+
+class UnknownLevelError(Error):
+    """
+    Raise when trying to access unknown level.
+
+    *********************************************
+    """
+
+    pass
+
+
+class UnknownFilterError(Error):
+    """
+    Raise when trying to use an unknown filter.
+
+    *********************************************
+    """
+
+    pass
+
+
+class PathaiaWarning(Warning):
+    """
+    Base of custom warnings.
+
+    ************************
+    """
+    pass
+
+
+class HasNoDataFolder(PathaiaWarning):
+    """
+    Raise when trying to read mrxs with no data folder.
+
+    ***************************************************
+    """
+
+    pass
+
+
+class InvalidArgument(Error):
+    """
+    Raise when trying to read mrxs with no data folder.
+
+    ***************************************************
+    """
+
+    pass