sage.symbolic.expression: Remove function deprecated in sagemath#32638 …

…(2021)

src/sage/symbolic/expression.pyx

@@ -409,32 +409,6 @@ include "pynac_impl.pxi"
 from sage.symbolic.symbols import symbol_table, register_symbol  # used to be defined in pynac_impl
 
 
-cpdef bint is_Expression(x):
-    """
-    Return True if ``x`` is a symbolic expression.
-
-    This method is deprecated.  Use :func:`isinstance` with
-    :class:`sage.structure.element.Expression` instead.
-
-    EXAMPLES::
-
-        sage: from sage.symbolic.expression import is_Expression
-        sage: is_Expression(x)
-        doctest:warning...
-        DeprecationWarning: is_Expression is deprecated;
-        use isinstance(..., sage.structure.element.Expression) instead
-        See https://github.com/sagemath/sage/issues/32638 for details.
-        True
-        sage: is_Expression(2)
-        False
-        sage: is_Expression(SR(2))
-        True
-    """
-    from sage.misc.superseded import deprecation
-    deprecation(32638, 'is_Expression is deprecated; use isinstance(..., sage.structure.element.Expression) instead')
-    return isinstance(x, Expression)
-
-
 cpdef bint is_SymbolicEquation(x):
     """
     Return True if *x* is a symbolic equation.