import math

local_funcs = {
    "acos": math.acos,
    "acosh": math.acosh,
    "asin": math.asin,
    "asinh": math.asinh,
    "atan": math.atan,
    "atan2": math.atan2,
    "atanh": math.atanh,
    "ceil": math.ceil,
    "cos": math.cos,
    "cosh": math.cosh,
    "degrees": math.degrees,
    "e_log": math.e,
    "erf": math.erf,
    "erfc": math.erfc,
    "exp": math.exp,
    "factorial": math.factorial,
    "floor": math.floor,
    "gamma": math.gamma,
    "log": math.log,
    "log10": math.log10,
    "pi": math.pi,
    "pow": math.pow,
    "radians": math.radians,
    "sin": math.sin,
    "sinh": math.sinh,
    "sqrt": math.sqrt,
    "tan": math.tan,
    "tanh": math.tanh,
}


def eval_expr(expr):
    if "__" in expr or "=" in expr:
        raise  # Disallow unsafe evaluations.
    return eval(expr, local_funcs)
