prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Autocompletion with Init-Signatures of C extension classes
  I don't quite get the autocompletion to work with C extension classes. These classes have a Signature (at least since python 3.4 by utilizing `__text_signature__`) but it seems IPython cannot autocomplete the parameters in `__text_signature__`.
  
  For example:
  
  ```
  >>> import pickle
  >>> import inspect
  >>> inspect.Signature.from_callable(pickle.Pickler)
  <Signature (file, protocol=None, fix_imports=True)>
  ```
  
  Note that the signature is saved as `__text_signature__`-attribute on ``pickle.Pickle``.
  
  I would expect that after printing`pickle.Pickler(` and then hitting TAB it would show:
  ```
  file=
  protocol=
  fix_imports=
  # other stuff
  ```
  but it doesn't. 
  
  Classes seem to be special in this regard - IPython is definitly able to get the parameters for functions and methods! It just doesn't work for classes.
  
  </issue>
  <code>
  [start of IPython/utils/dir2.py]
  1 # encoding: utf-8
  2 """A fancy version of Python's builtin :func:`dir` function.
  3 """
  4 
  5 # Copyright (c) IPython Development Team.
  6 # Distributed under the terms of the Modified BSD License.
  7 
  8 import inspect
  9 from .py3compat import string_types
  10 
  11 
  12 def safe_hasattr(obj, attr):
  13     """In recent versions of Python, hasattr() only catches AttributeError.
  14     This catches all errors.
  15     """
  16     try:
  17         getattr(obj, attr)
  18         return True
  19     except:
  20         return False
  21 
  22 
  23 def dir2(obj):
  24     """dir2(obj) -> list of strings
  25 
  26     Extended version of the Python builtin dir(), which does a few extra
  27     checks.
  28 
  29     This version is guaranteed to return only a list of true strings, whereas
  30     dir() returns anything that objects inject into themselves, even if they
  31     are later not really valid for attribute access (many extension libraries
  32     have such bugs).
  33     """
  34 
  35     # Start building the attribute list via dir(), and then complete it
  36     # with a few extra special-purpose calls.
  37 
  38     try:
  39         words = set(dir(obj))
  40     except Exception:
  41         # TypeError: dir(obj) does not return a list
  42         words = set()
  43 
  44     # filter out non-string attributes which may be stuffed by dir() calls
  45     # and poor coding in third-party modules
  46 
  47     words = [w for w in words if isinstance(w, string_types)]
  48     return sorted(words)
  49 
  50 
  51 def get_real_method(obj, name):
  52     """Like getattr, but with a few extra sanity checks:
  53 
  54     - If obj is a class, ignore its methods
  55     - Check if obj is a proxy that claims to have all attributes
  56     - Catch attribute access failing with any exception
  57     - Check that the attribute is a callable object
  58 
  59     Returns the method or None.
  60     """
  61     if inspect.isclass(obj):
  62         return None
  63 
  64     try:
  65         canary = getattr(obj, '_ipython_canary_method_should_not_exist_', None)
  66     except Exception:
  67         return None
  68 
  69     if canary is not None:
  70         # It claimed to have an attribute it should never have
  71         return None
  72 
  73     try:
  74         m = getattr(obj, name, None)
  75     except Exception:
  76         return None
  77 
  78     if callable(m):
  79         return m
  80 
  81     return None
  82
  [end of IPython/utils/dir2.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/IPython/utils/dir2.py b/IPython/utils/dir2.py
  --- a/IPython/utils/dir2.py
  +++ b/IPython/utils/dir2.py
  @@ -41,6 +41,9 @@
           # TypeError: dir(obj) does not return a list
           words = set()
   
  +    if safe_hasattr(obj, '__class__'):
  +        words |= set(dir(obj.__class__))
  +
       # filter out non-string attributes which may be stuffed by dir() calls
       # and poor coding in third-party modules
  
verification_info: {"golden_diff": "diff --git a/IPython/utils/dir2.py b/IPython/utils/dir2.py\n--- a/IPython/utils/dir2.py\n+++ b/IPython/utils/dir2.py\n@@ -41,6 +41,9 @@\n         # TypeError: dir(obj) does not return a list\n         words = set()\n \n+    if safe_hasattr(obj, '__class__'):\n+        words |= set(dir(obj.__class__))\n+\n     # filter out non-string attributes which may be stuffed by dir() calls\n     # and poor coding in third-party modules\n", "issue": "Autocompletion with Init-Signatures of C extension classes\nI don't quite get the autocompletion to work with C extension classes. These classes have a Signature (at least since python 3.4 by utilizing `__text_signature__`) but it seems IPython cannot autocomplete the parameters in `__text_signature__`.\r\n\r\nFor example:\r\n\r\n```\r\n>>> import pickle\r\n>>> import inspect\r\n>>> inspect.Signature.from_callable(pickle.Pickler)\r\n<Signature (file, protocol=None, fix_imports=True)>\r\n```\r\n\r\nNote that the signature is saved as `__text_signature__`-attribute on ``pickle.Pickle``.\r\n\r\nI would expect that after printing`pickle.Pickler(` and then hitting TAB it would show:\r\n```\r\nfile=\r\nprotocol=\r\nfix_imports=\r\n# other stuff\r\n```\r\nbut it doesn't. \r\n\r\nClasses seem to be special in this regard - IPython is definitly able to get the parameters for functions and methods! It just doesn't work for classes.\n", "before_files": [{"content": "# encoding: utf-8\n\"\"\"A fancy version of Python's builtin :func:`dir` function.\n\"\"\"\n\n# Copyright (c) IPython Development Team.\n# Distributed under the terms of the Modified BSD License.\n\nimport inspect\nfrom .py3compat import string_types\n\n\ndef safe_hasattr(obj, attr):\n    \"\"\"In recent versions of Python, hasattr() only catches AttributeError.\n    This catches all errors.\n    \"\"\"\n    try:\n        getattr(obj, attr)\n        return True\n    except:\n        return False\n\n\ndef dir2(obj):\n    \"\"\"dir2(obj) -> list of strings\n\n    Extended version of the Python builtin dir(), which does a few extra\n    checks.\n\n    This version is guaranteed to return only a list of true strings, whereas\n    dir() returns anything that objects inject into themselves, even if they\n    are later not really valid for attribute access (many extension libraries\n    have such bugs).\n    \"\"\"\n\n    # Start building the attribute list via dir(), and then complete it\n    # with a few extra special-purpose calls.\n\n    try:\n        words = set(dir(obj))\n    except Exception:\n        # TypeError: dir(obj) does not return a list\n        words = set()\n\n    # filter out non-string attributes which may be stuffed by dir() calls\n    # and poor coding in third-party modules\n\n    words = [w for w in words if isinstance(w, string_types)]\n    return sorted(words)\n\n\ndef get_real_method(obj, name):\n    \"\"\"Like getattr, but with a few extra sanity checks:\n\n    - If obj is a class, ignore its methods\n    - Check if obj is a proxy that claims to have all attributes\n    - Catch attribute access failing with any exception\n    - Check that the attribute is a callable object\n\n    Returns the method or None.\n    \"\"\"\n    if inspect.isclass(obj):\n        return None\n\n    try:\n        canary = getattr(obj, '_ipython_canary_method_should_not_exist_', None)\n    except Exception:\n        return None\n\n    if canary is not None:\n        # It claimed to have an attribute it should never have\n        return None\n\n    try:\n        m = getattr(obj, name, None)\n    except Exception:\n        return None\n\n    if callable(m):\n        return m\n\n    return None\n", "path": "IPython/utils/dir2.py"}]}