Remove docstring; Fix obj.__dir__()

This reverts commit ddeda78478510cb077df9ed6edb19e19bdd7cf36.

amalgamate.py

@@ -5,8 +5,7 @@ import sys
 import time
 from typing import List, Dict
 
-if os.system("python prebuild.py") != 0:
+assert os.system("python prebuild.py") == 0
-    assert os.system("python3 prebuild.py") == 0
 
 ROOT = 'include/pocketpy'
 PUBLIC_HEADERS = ['config.h', 'export.h', 'linalg.h', 'pocketpy.h']
@@ -157,4 +156,4 @@ if sys.platform in ['linux', 'darwin']:
 print("amalgamated/pocketpy.h")
 
 shutil.copy("amalgamated/pocketpy.h", "plugins/flutter/pocketpy/src/pocketpy.h")
-shutil.copy("amalgamated/pocketpy.c", "plugins/flutter/pocketpy/src/pocketpy.c")
+shutil.copy("amalgamated/pocketpy.c", "plugins/flutter/pocketpy/src/pocketpy.c")

python/builtins.py

@@ -82,24 +82,11 @@ def sorted(iterable, key=None, reverse=False):
     return a
 
 def dir(obj=None):
-    """
-    dir([object]) -> list of strings
-    
-    If called without an argument, return the names in the current scope.
-    Else, return an alphabetized list of names comprising (some of) the attributes
-    of the given object, and of attributes reachable from it.
-    If the object supplies a method named __dir__, it will be used; otherwise
-    the default dir() logic is used and returns:
-      for a module object: the module's attributes.
-      for a class object: its attributes.
-      for any other object: its attributes, its class's attributes.
-    """
-    
     if obj is None:
         return list(globals().keys())
     
     if hasattr(obj, "__dir__"):
-        return obj.__dir__
+        return obj.__dir__()
     
     attributes = set()
     # Set object attributes.