title: Enforce precision in decimal python
body: <p>In some environments, exact decimals (numerics, numbers...) are defined with <code>scale</code> and <code>precision</code>, with scale being all significant numbers, and precision being those right of the decimal point. I want to use python's decimal implementation to raise an error, if the precision of the casted string is higher than the one defined by the implementation.</p>
  
  <p>So for example, I have an environment, where <code>scale = 4</code> and <code>precision = 2</code>.
  How can I achieve these commands to raise an error, because their precision exceeds that of the implementation?</p>
  
  <pre><code>decimals.Decimal('1234.1')
  decimals.Decimal('0.123')
  </code></pre>