title: Python decimal.InvalidOperation error
body: <p>i'm always getting this error when running something like this:</p>
  
  <pre><code>from decimal import *
  getcontext().prec =30
  
  b=("2/3")
  
  Decimal(b)
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "Test.py", line 6, in &lt;module&gt;
      Decimal(b)
  decimal.InvalidOperation: [&lt;class 'decimal.ConversionSyntax'&gt;]
  </code></pre>
  
  <p>Also, why do i get this result from the console?</p>
  
  <pre><code>&gt;&gt;&gt; Decimal(2/3)
  Decimal('0.66666666666666662965923251249478198587894439697265625')
  </code></pre>
  
  <p>Thanks</p>