title: how to merge multiple dataframe in a loop by using classes
body: <p>Uses class and define functions to do pd.merge between multiple dataframes.
  Error shown.</p>
  
  <p>I tried this, shown:</p>
  
  <pre><code>ValueError:can not merge DataFrame with instance of type 
  &lt;class '__main__.Merge'&gt;
  </code></pre>
  
  <pre><code>class Merge(object):
      def __init__(self, table1, table2):
          self.table1 = table1
          self.table2 = table2
      def merged(self):
          return pd.merge(self.table1,self.table2, how ='left', on ='TITLE')
  a=Merge(df4,df6);b=Merge(a,df8);c=Merge(b,df10);d=Merge(c,df12);e=Merge(d,df14);f=Merge(e,df16)
  for obj in [a,b,c,d,e,f]:
      obj.merged()
  </code></pre>
  
  <p>Is it possible to use class in order to loop them and loop everything in one go?</p>