remove some cast_unicode

IPython/core/display.py

@@ -16,7 +16,8 b' from copy import deepcopy'
 from os.path import splitext
 from pathlib import Path, PurePath
 
-from IPython.utils.py3compat import cast_unicode
+from typing import Optional
+
 from IPython.testing.skipdoctest import skip_doctest
 from . import display_functions
 
@@ -518,7 +519,7 b' class SVG(DisplayObject):'
     _read_flags = 'rb'
     # wrap data in a property, which extracts the <svg> tag, discarding
     # document headers
-    _data = None
+    _data: Optional[str] = None
 
     @property
     def data(self):
@@ -540,8 +541,10 b' class SVG(DisplayObject):'
             # fallback on the input, trust the user
             # but this is probably an error.
             pass
-        svg = cast_unicode(svg)
-        self._data = svg
+        if isinstance(svg, bytes):
+            self._data = svg.decode(errors="replace")
+        else:
+            self._data = svg
 
     def _repr_svg_(self):
         return self._data_and_metadata()

IPython/lib/latextools.py

@@ -18,7 +18,6 b' from IPython.utils.process import find_cmd, FindCmdError'
 from traitlets.config import get_config
 from traitlets.config.configurable import SingletonConfigurable
 from traitlets import List, Bool, Unicode
-from IPython.utils.py3compat import cast_unicode
 
 
 class LaTeXTool(SingletonConfigurable):
@@ -58,8 +57,9 b' class LaTeXTool(SingletonConfigurable):'
         ).tag(config=True)
 
 
-def latex_to_png(s, encode=False, backend=None, wrap=False, color='Black',
-                 scale=1.0):
+def latex_to_png(
+    s: str, encode=False, backend=None, wrap=False, color="Black", scale=1.0
+):
     """Render a LaTeX string to PNG.
 
     Parameters
@@ -80,7 +80,7 b" def latex_to_png(s, encode=False, backend=None, wrap=False, color='Black',"
     None is returned when the backend cannot be used.
 
     """
-    s = cast_unicode(s)
+    assert isinstance(s, str)
     allowed_backends = LaTeXTool.instance().backends
     if backend is None:
         backend = allowed_backends[0]

IPython/utils/_process_win32.py

@@ -170,7 +170,7 b' try:'
             # not really a cl-arg, fallback on _process_common
             return py_arg_split(commandline, posix=posix, strict=strict)
         argvn = c_int()
-        result_pointer = CommandLineToArgvW(py3compat.cast_unicode(commandline.lstrip()), ctypes.byref(argvn))
+        result_pointer = CommandLineToArgvW(commandline.lstrip(), ctypes.byref(argvn))
         result_array_type = LPCWSTR * argvn.value
         result = [arg for arg in result_array_type.from_address(ctypes.addressof(result_pointer.contents))]
         retval = LocalFree(result_pointer)