def extract_the(node, node_type):
    """Extracts the node of type node_type from the provided node.
    
    - If the node is itself of node_type, returns node.
    - If the node is a suite, it must contain exactly one node of the provided
      type in its body.
    
    """
    if isinstance(node, node_type):
        return node
    try:
        body = node.body
    except AttributeError:
        raise cypy.Error(
            "Expecting suite containing a single %s, or a %s, but got %s." %
            (node_type.__name__, node_type.__name__, type(node).__name__))
    
    if len(body) != 1 or not isinstance(body[0], node_type):
        raise cypy.Error(
            "The body must contain exactly one node of type %s." %
            node_type.__name__)
    return body[0]
Extracts the node of type node_type from the provided node.
    
    - If the node is itself of node_type, returns node.
    - If the node is a suite, it must contain exactly one node of the provided
      type in its body.