code: def inject_content(self, content, inject_string):
          
          inject_string = _unicode(inject_string)
          content = self.wrapper_match.sub("", _unicode(content))
          if self.override_match:
              sprinter_overrides = self.override_match.search(content)
              if sprinter_overrides:
                  content = self.override_match.sub("", content)
                  sprinter_overrides = sprinter_overrides.groups()[0]
              else:
                  sprinter_overrides = ""
          content += """
  %s
  %s
  %s
  """ % (self.wrapper, inject_string.rstrip(), self.wrapper)
          if self.override_match:
              content += sprinter_overrides.rstrip() + "\n"
          return content
docs: Inject inject_string into a text buffer, wrapped with
          #{{ wrapper }} comments if condition lambda is not
          satisfied or is None. Remove old instances of injects if they
          exist.