code: def lowercase_attr_names(tag):
      
      # Use list comprehension instead of dict comprehension for 2.6 support
      tag.attrs = dict([
          (key.lower(), value)
          for key, value in iteritems(tag.attrs)
      ])
docs: Lower-case all attribute names of the provided BeautifulSoup tag.
      Note: this mutates the tag's attribute names and does not return a new
      tag.
  
      :param Tag: BeautifulSoup tag