title: Return dataframe as class method
body: <p>I would like to create report objects that are dataframes when object is created. the code is meant to read a file and do some filtering as part of the instantiation and calling load method</p>
  
  <pre><code>class Report:
      def __init__(self,c = ['red','green','blue'],y = [2015,2016,2017,2018,2019]):
          self.color = c
          self.years = y
  
      def load(self):
          df = pd.read_excel(r"C:\Users\ger\Desktop\sample.xlsx",sheet_name='sht1')
          df = df.loc[(df['color'].isin(self.color) &amp; 
                       df['year'].isin(self.years)),:]
          return df
  
  # none of these below seems to work though
  r1 = Report().load()
  
  # or
  r1 = Report()
  r1 = r1.load()
  </code></pre>
  
  <p>The expected result would be dataframe with color and year fields as mentioned in init or as defined within the Report() call. Any thoughts are greatly appreciated</p>