title: Calculate formula in string
body: <p>Given is a formula(y = mx + b) as a string and a tuple(x, y) with x and y.
  I s there a python function that uses x and y and calculates the formula ?</p>
  <p>As an an example:</p>
  <pre><code>def calculate(&quot;y = -4x + 6&quot;, (1, 2)) ➞ True
  </code></pre>
  <p>2 = -4*1 + 6 ➞ True</p>