title: Kivy: How to convert user input into int or float
body: <p>When using <code>TextInput</code> in Kivy, everything that is entered is kept as a string, even when the input is restricted to characters that represent <code>float</code>s or <code>int</code>s using <code>input_filter</code>. How can <code>TextInput.text</code> be converted into an actual float or int type so that I can do calculations with it?</p>