Move class documentation to the docstring.

docs/datamodel.rst

@@ -15,17 +15,11 @@ Data Model
 This module provides the :class:`DataModel` class that provides the basic
 user-level API to the *Yangson* library.
 
-.. class:: DataModel(yltxt: str, mod_path: List[str] )
-
-   This class represents a high-level view of the YANG data model. Its
-   constructor has two arguments:
-
-   - **yltxt** – JSON text with YANG library data;
-   - **mod_path** – list of filesystem paths from which the YANG modules
-     that are listed in the YANG library data can be retrieved.
+.. autoclass:: DataModel(yltxt: str, mod_path: List[str] )
 
    It is a *singleton* class which means that only one instance can be
-   created.
+   created. This limitation corresponds to the fact that it is not
+   possible to work with multiple data models at the same time.
 
    :class:`DataModel` is also re-exported by the main package, so it
    can also be imported directly from there:

yangson/datamodel.py

@@ -10,16 +10,14 @@ from .schema import (BadSchemaNodeType, DataNode, GroupNode,
 from .typealiases import *
 
 class DataModel(metaclass=Singleton):
-    """Singleton class representing the entry point to the YANG data model."""
+    """The basic entry point to the YANG data model.
 
-    def __init__(self, yltxt: str, mod_path: List[str]) -> None:
-        """Initialize the class instance.
+    :param yltxt: JSON text with YANG library data
+    :param mod_path: list of directories where to look for YANG modules
+    """
 
-        :param yltxt: JSON text containing YANG library data
-        :param mod_path: list of filesystem paths from which
-                         YANG modules listed in YANG library
-                         can be retrieved.
-        """
+    def __init__(self, yltxt: str, mod_path: List[str]) -> None:
+        """Initialize the class instance."""
         Context.schema = GroupNode()
         try:
             yl = json.loads(yltxt)