IMetadataAccess class

Defines methods that are required for access to metadata of a document, if format supports it.

The IMetadataAccess type exposes the following members:

Method	Description
`get_metadata(self)`	Retrieves a dictionary with document’s metadata.
`change_metadata(self, metadata_item)`	Changes the specified item of metadata from `MetadataCollection` or adds a new one, if not present.