##
13.5.5 Expat error constants

The following constants are provided in the `errors` object of the `xml.parsers.expat` module. These constants are useful in interpreting some of the attributes of the `ExpatError` exception objects raised when an error has occurred.

The `errors` object has the following attributes:

`XML_ERROR_ASYNC_ENTITY`

`XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF`
  An entity reference in an attribute value referred to an external entity instead of an internal entity.

`XML_ERROR_BAD_CHAR_REF`
  A character reference referred to a character which is illegal in XML (for example, character `0`, or ``&#0;`').

`XML_ERROR_BINARY_ENTITY_REF`
  An entity reference referred to an entity which was declared with a notation, so cannot be parsed.

`XML_ERROR_DUPLICATE_ATTRIBUTE`
  An attribute was used more than once in a start tag.

`XML_ERROR_INCORRECT_ENCODING`

`XML_ERROR_INVALID_TOKEN`
  Raised when an input byte could not properly be assigned to a character; for example, a NUL byte (value `0`) in a UTF-8 input stream.

`XML_ERROR_JUNK_AFTER_DOC_ELEMENT`
  Something other than whitespace occurred after the document element.

`XML_ERROR_MISPLACED_XML_PI`
  An XML declaration was found somewhere other than the start of the input data.

`XML_ERROR_NO_ELEMENTS`
  The document contains no elements (XML requires all documents to contain exactly one top-level element)..

`XML_ERROR_NO_MEMORY`
  Expat was not able to allocate memory internally.

`XML_ERROR_PARAM_ENTITY_REF`
  A parameter entity reference was found where it was not allowed.

`XML_ERROR_PARTIAL_CHAR`

`XML_ERROR_RECURSIVE_ENTITY_REF`
  An entity reference contained another reference to the same entity; possibly via a different name, and possibly indirectly.

`XML_ERROR_SYNTAX`
  Some unspecified syntax error was encountered.

`XML_ERROR_TAG_MISMATCH`
  An end tag did not match the innermost open start tag.

`XML_ERROR_UNCLOSED_TOKEN`
  Some token (such as a start tag) was not closed before the end of the stream or the next token was encountered.

`XML_ERROR_UNDEFINED_ENTITY`
  A reference was made to a entity which was not defined.

`XML_ERROR_UNKNOWN_ENCODING`
  The document encoding is not supported by Expat.