old_contents: """
  The collection of mixins to be used in core classes.
  
  Would be interesting only if you are planning to hack into Xentica
  core functionality.
  
  """
  import inspect
  
  import xentica.core.base
  from xentica.core.exceptions import XenticaException
  
  __all__ = ['BscaDetectorMixin', ]
  
  
  class BscaDetectorMixin:
      """
      Add a functionlality to detect BSCA class instances holding current class.
  
      All methods are for private use only.
  
      """
  
      @property
      def bsca(self):
          """
          Get a BSCA instance holding current class.
  
          Objects tree is scanned up to top and first instance found is returned.
  
          """
          frame = inspect.currentframe()
          while frame is not None:
              for l in frame.f_locals.values():
                  if hasattr(l, "__get__"):
                      continue
                  if isinstance(l, xentica.core.base.BSCA):
                      return l
              frame = frame.f_back
          raise XenticaException("BSCA not detected")
  
      @property
      def _holder_frame(self):
          """
          Get a frame of class instance holding current class.
  
          Objects tree is scanned up to top and first instance found is returned.
  
          """
          # TODO: detect base class by scanning inheritance tree:
          # inspect.getclasstree(inspect.getmro(type(self)))
          frame = inspect.currentframe().f_back.f_back.f_back
          while isinstance(frame.f_locals.get('self', ''), self.base_class):
              frame = frame.f_back
          return frame
  
      @property
      def _holder(self):
          """Get an instance from a frame found by :meth:`_holder_frame`."""
          return self._holder_frame.f_locals['self']
  
new_contents: """
  The collection of mixins to be used in core classes.
  
  Would be interesting only if you are planning to hack into Xentica
  core functionality.
  
  """
  import inspect
  
  import xentica.core.base
  from xentica.core.exceptions import XenticaException
  
  __all__ = ['BscaDetectorMixin', ]
  
  
  class BscaDetectorMixin:
      """
      Add a functionlality to detect BSCA class instances holding current class.
  
      All methods are for private use only.
  
      """
  
      @property
      def bsca(self):
          """
          Get a BSCA instance holding current class.
  
          Objects tree is scanned up to top and first instance found is returned.
  
          """
          frame = inspect.currentframe()
          while frame is not None:
              for local in frame.f_locals.values():
                  if hasattr(local, "__get__"):
                      continue
                  if isinstance(local, xentica.core.base.BSCA):
                      return local
              frame = frame.f_back
          raise XenticaException("BSCA not detected")
  
      @property
      def _holder_frame(self):
          """
          Get a frame of class instance holding current class.
  
          Objects tree is scanned up to top and first instance found is returned.
  
          """
          # As an option, we can detect base class by scanning inheritance tree:
          # inspect.getclasstree(inspect.getmro(type(self)))
          frame = inspect.currentframe().f_back.f_back.f_back
          while isinstance(frame.f_locals.get('self', ''), self.base_class):
              frame = frame.f_back
          return frame
  
      @property
      def _holder(self):
          """Get an instance from a frame found by :meth:`_holder_frame`."""
          return self._holder_frame.f_locals['self']
  
subject: Fix pylint issues in core.mixins (#30)