feat: add doc_ids parameter to Table.get

See #504
Closes #486

tests/test_tinydb.py

@@ -366,7 +366,10 @@ def test_get_ids(db: TinyDB):
     assert db.get(doc_id=el.doc_id) == el
     assert db.get(doc_id=float('NaN')) is None  # type: ignore
 
-
+def test_get_multiple_ids(db: TinyDB):
+    el = db.all()
+    assert db.get(doc_id=[x.doc_id for x in el]) == el
+
 def test_get_invalid(db: TinyDB):
     with pytest.raises(RuntimeError):
         db.get()

tinydb/table.py

@@ -279,30 +279,43 @@ def search(self, cond: QueryLike) -> List[Document]:
     def get(
         self,
         cond: Optional[QueryLike] = None,
-        doc_id: Optional[int] = None,
-    ) -> Optional[Document]:
+        doc_id: Optional[Union[int , List]] = None,
+        doc_ids: Optional[List] = None
+    ) -> Optional[Union[Document , List[Document]]]:
         """
         Get exactly one document specified by a query or a document ID.
-
+        However if muliple document IDs are given then returns all docu-
+        ments in a list.
+        
         Returns ``None`` if the document doesn't exist.
 
         :param cond: the condition to check against
         :param doc_id: the document's ID
+        :param doc_ids: the document's IDs(multiple)
 
-        :returns: the document or ``None``
-        """
-
+        :returns: the document(s) or ``None``
+        """      
+        table = self._read_table()
         if doc_id is not None:
             # Retrieve a document specified by its ID
-            table = self._read_table()
             raw_doc = table.get(str(doc_id), None)
 
             if raw_doc is None:
                 return None
 
             # Convert the raw data to the document class
             return self.document_class(raw_doc, doc_id)
+        elif doc_ids is not None:
+            # Filter the table by extracting out all those documents which have doc id
+            # specified in the doc_id list.
+            set_doc_id = set(doc_ids) # Since Doc Ids will be unique, making it a set to make sure constant lookup
+            raw_docs = dict(filter(lambda item: int(item[0]) in set_doc_id, table.items()))
+            if raw_docs is None:
+                return None
 
+            ## Now return the filtered documents in form of list
+            return list(map(lambda x:self.document_class(raw_docs[str(x)] , int(x)) , raw_docs.keys()))
+
         elif cond is not None:
             # Find a document specified by a query
             # The trailing underscore in doc_id_ is needed so MyPy
@@ -318,7 +331,7 @@ def get(
 
             return None
 
-        raise RuntimeError('You have to pass either cond or doc_id')
+        raise RuntimeError('You have to pass either cond or doc_id or doc_ids')
 
     def contains(
         self,