title: Rpy2: calling to function conaining dots
body: <p>I'm tring to run a R function in Pyton via Jupyter Notebook.
  the problem is, that my function name (from mice lib) - containing dot.
  the name of the function is <code>md.pattern</code>, and this is the code that I'm tring to run:</p>
  
  <pre><code>from rpy2.robjects.packages import importr
  mice = importr('mice')
  mice.md.pattern(train)
  </code></pre>
  
  <p>and this is the error that I get:</p>
  
  <pre><code>AttributeError: module 'mice' has no attribute 'md'
  </code></pre>
  
  <p>I also tried to run:</p>
  
  <pre><code>from rpy2.robjects.packages import importr
  mice = importr('mice')
  
  pattern = robjects.r("md.pattern")
  mice.pattern(train)
  </code></pre>
  
  <p>and get the same error.</p>