Repository: sympy/sympy
File: sympy/core/expr.py (Python)

Code before:
        n = evalf

    is_scalar = True  # self derivative is 1

    @property
    def is_hermitian(self):

        imply_hermitian = [
            self.is_real,
            self.is_composite,
            self.is_even,
            self.is_integer,
            self.is_irrational,
            self.is_negative,
            self.is_nonnegative,
            self.is_nonpositive,
            self.is_nonzero,
            self.is_odd,
            self.is_positive,
            self.is_prime,
            self.is_rational,
            self.is_zero,
        ]

        if any(imply_hermitian):
            return True

        if callable(getattr(self, '_eval_is_hermitian', None)):
            return self._eval_is_hermitian()
        return None

    @property
    def is_antihermitian(self):
        imply_antihermitian = [
            self.is_imaginary,
            self.is_zero
        ]
        if any(imply_antihermitian):
            return True
        if callable(getattr(self, '_eval_is_antihermitian', None)):
            return self._eval_is_antihermitian()
        return None

    @property
    def _diff_wrt(self):
        """Return True if one can differentiate with respect to this
        object, else False.

        Explanation
        ===========


Review comment (suggestion):
This should accomplish the same thing:
```python
if self.is_real:
    return True
```

All of those other properties imply hermitian because they imply real. 

Code after:
        n = evalf

    is_scalar = True  # self derivative is 1

    @property
    def is_hermitian(self):
        if self.is_real:
            return True

        if callable(getattr(self, '_eval_is_hermitian', None)):
            return self._eval_is_hermitian()
        return None

    @property
    def is_antihermitian(self):
        if self.is_imaginary or self.is_zero:
            return True

        if callable(getattr(self, '_eval_is_antihermitian', None)):
            return self._eval_is_antihermitian()
        return None

    @property
    def _diff_wrt(self):
        """Return True if one can differentiate with respect to this
        object, else False.

        Explanation
        ===========

        Subclasses such as Symbol, Function and Derivative return True
        to enable derivatives wrt them. The implementation in Derivative
        separates the Symbol and non-Symbol (_diff_wrt=True) variables and
        temporarily converts the non-Symbols into Symbols when performing
        the differentiation. By default, any object deriving from Expr
        will behave like a scalar with self.diff(self) == 1. If this is
        not desired then the object must also set `is_scalar = False` or
        else define an _eval_derivative routine.

        Note, see the docstring of Derivative for how this should work
        mathematically. In particular, note that expr.subs(yourclass, Symbol)
        should be well-defined on a structural level, or this will lead to
        inconsistent results.

        Examples
        ========

        >>> from sympy import Expr
        >>> e = Expr()
        >>> e._diff_wrt
        False