Implement and use _update_equation_with_symbol_definitions function

[fhightower]

What?

I would like to implement the _update_equation_with_symbol_definitions function something like the code below:

def _update_equation_with_symbol_definitions(equation: str):
    """Find all letters in the given equation and replace them with the appropriate call to the sympy.symbols function."""
    from strings import asciiLetters

    ascii_letters = [char for char in equation if char in asciiLetters()]

    for letter in set(ascii_letters):
        equation = equation.replace(letter, f'sympy.symbols("{letter}")')

    return equation

Then, I would like to use it in the equation_solve function so that someone can pass in an equation like y = x ^ 3 + 2 and both y and x will be converted to sympy symbols.