title: Converting dictionary to dataframe with key as column names and value of key as column values of the dataframe
body: <p>Converting the nested dictionary to dataframe with, dictionary <strong>keys</strong> as <strong>column names</strong> and <strong>values</strong> corresponding to those keys as <strong>column values</strong> of the dataframe.</p>
  <p>I'm new to python and have tried several approaches but failed in achieving so, please help.</p>
  <pre class="lang-py prettyprint-override"><code>dict = {
      'sheet1': {
          'col1': ['a', 'b', 'c', 'd', 'e'],
          'col2': ['p', 'q', 'r', 's', 't'],
          'col3': ['l', 'm', 'n', 'o'],
          'col4': ['e', 'b', 'w', 't', 'b']
      },
      'sheet2': {
          'col1': ['r', 'w', 'y', 'g', 'r'],
          'col2': ['q', 'y', 'f', 'w'],
          'col3': ['w', 'g', 4, 2, 'd']
      }
  }
  </code></pre>
  <pre><code>output: 
  col1    col2   col3   col4
  a       p       l      e
  b       q       m      b
  c       r       n      w
  d       s       o      t
  e       t       nan    b
  r       q       w      nan
  w       y       g      nan
  y       f       4      nan
  g       w       2      nan
  r      nan      d      nan
  </code></pre>