Add documentation to custom errors

amanuensis/errors.py

@@ -3,10 +3,21 @@ class AmanuensisError(Exception):
 	pass
 
 class MissingConfigError(AmanuensisError):
+	"""A config file is missing that was expected to be present"""
 	pass
 
 class MalformedConfigError(AmanuensisError):
+	"""A config file could not be read and parsed"""
 	pass
 
 class ReadOnlyError(AmanuensisError):
+	"""A config was edited in readonly mode"""
+	pass
+
+class InternalMisuseError(AmanuensisError):
+	"""An internal helper method was called wrongly"""
+	pass
+
+class IndexMismatchError(AmanuensisError):
+	"""An id was obtained from an index, but the object doesn't exist"""
 	pass