title: Transform dictionary key-value pairs to list of tuples
body: <p>I have a dictionary of lists:</p>
  <pre><code>dic = {'contig_100003': ['contig_14576'],  'contig_100022': ['contig_96468'],  'contig_100023': ['contig_24939', 'contig_33444', 'contig_72441']}
  </code></pre>
  <p>And I would like to get a list (including the key) of it:</p>
  <pre><code>List = [(contig_100003','contig_14576'), (contig_100022','contig_96468'), (contig_100023','contig_24939', 'contig_33444', 'contig_72441')]
  </code></pre>
  <p>However, my code cannot get rid of the internal/value list:</p>
  <pre><code>list(dic.items())
  [('contig_100003', ['contig_14576']),
   ('contig_100022', ['contig_96468']),
   ('contig_100023', ['contig_24939', 'contig_33444', 'contig_72441'])]
  </code></pre>