Update stub for zlib

stdlib/2.7/zlib.pyi

@@ -1,7 +1,5 @@
 # Stubs for zlib (Python 2.7)
 
-class error(Exception): ...
-
 DEFLATED = ... # type: int
 DEF_MEM_LEVEL = ... # type: int
 MAX_WBITS = ... # type: int
@@ -17,20 +15,28 @@ Z_HUFFMAN_ONLY = ... # type: int
 Z_NO_FLUSH = ... # type: int
 Z_SYNC_FLUSH = ... # type: int
 
+
+class error(Exception): ...
+
+
+class Compress:
+    def compress(self, data: str) -> str: ...
+    def flush(self) -> str: ...
+    def copy(self) -> "Compress": ...
+
+
+class Decompress:
+    unused_data = ...  # type: str
+    unconsumed_tail = ...  # type: str
+    def decompress(self, data: str, max_length: int = ...) -> str: ...
+    def flush(self) -> str: ...
+    def copy(self) -> "Decompress": ...
+
+
 def adler32(data: str, value: int = ...) -> int: ...
 def compress(data: str, level: int = ...) -> str: ...
+def compressobj(level: int = ..., method: int = ..., wbits: int = ...,
+                memlevel: int = ..., strategy: int = ...) -> Compress: ...
 def crc32(data: str, value: int = ...) -> int: ...
 def decompress(data: str, wbits: int = ..., bufsize: int = ...) -> str: ...
-
-class compressobj:
-    def __init__(self, level: int = ..., method: int = ..., wbits: int = ..., memlevel: int = ...,
-                 strategy: int = ...) -> None: ...
-    def copy(self) -> "compressobj": ...
-    def compress(self, data: str) -> str: ...
-    def flush(self) -> None: ...
-
-class decompressobj:
-    def __init__(self, wbits: int = ...) -> None: ...
-    def copy(self) -> "decompressobj": ...
-    def decompress(self, data: str, max_length: int = ...) -> str: ...
-    def flush(self) -> None: ...
+def decompressobj(wbits: int = ...) -> Decompress: ...