old_contents: #!/usr/bin/env python
  # coding: utf-8
  
  
  from table.utils import Accessor
  
  
  class Column(object):
      
      instance_order = 0
  
      def __init__(self, field=None, attrs={}, header=None, header_attrs={}):
          self.accessor = Accessor(field)
          self.attrs = attrs
          self.header = ColumnHeader(text=header, attrs=header_attrs)
          self.instance_order = Column.instance_order
          Column.instance_order += 1
  
      def render_attrs(self):
          """ Render attributes of <td> to html.
          """
          html = ''
          for attr in self.attrs:
              html = html + '{0}={1}'.format(attr, self.attrs.get(attr))
          return html
  
      def render(self, obj):
          """ Render cell for current obj. 
          """
          return self.accessor.resolve(obj)
  
  class ColumnHeader(object):
  
      def __init__(self, text=None, attrs={}):
          self.text = text
          self.attrs = attrs
          
      def render_attrs(self):
          """ Render attributes of <th> to html.
          """
          html = ''
          for attr in self.attrs:
              html = html + '{0}={1}'.format(attr, self.attrs.get(attr))
          return html
  
new_contents: #!/usr/bin/env python
  # coding: utf-8
  
  
  from table.utils import Accessor
  
  
  class Column(object):
      
      instance_order = 0
  
      def __init__(self, field=None, attrs=None, header=None, header_attrs=None):
          self.accessor = Accessor(field)
          self.attrs = attrs
          self.header = ColumnHeader(text=header, attrs=header_attrs)
          self.instance_order = Column.instance_order
          Column.instance_order += 1
  
      def render_attrs(self):
          """ Render attributes of <td> to html.
          """
          html = ''
          for attr in self.attrs:
              html = html + '{0}={1}'.format(attr, self.attrs.get(attr))
          return html
  
      def render(self, obj):
          """ Render cell for current obj. 
          """
          return self.accessor.resolve(obj)
  
  class ColumnHeader(object):
  
      def __init__(self, text=None, attrs={}):
          self.text = text
          self.attrs = attrs
          
      def render_attrs(self):
          """ Render attributes of <th> to html.
          """
          html = ''
          for attr in self.attrs:
              html = html + '{0}={1}'.format(attr, self.attrs.get(attr))
          return html
  
subject: fix pylint warnings: do not use {} as default argument