class_docstr: Provides methods to allow conversion between sheet and matrix
  coordinates.
code: def __set_xdensity(self, density):
      self.__xdensity = density
      self.__xstep = 1.0 / density
  
imports: import numpy
  from .boundingregion import BoundingBox
  from .util import datetime_types
label_desc: Use image node_id 5 for calling the SheetCoordinateSystem obj's underlying member method code with example usage: obj.__set_xdensity(density) without return types