code: def _prop_descriptions(self):
      return """\
          coloring
              Determines the coloring method showing the contour
              values. If "fill", coloring is done evenly between each
              contour level If "heatmap", a heatmap gradient coloring
              is applied between each contour level. If "lines",
              coloring is done on the contour lines. If "none", no
              coloring is applied on this trace.
          end
              Sets the end contour level value. Must be more than
              `contours.start`
          labelfont
              Sets the font used for labeling the contour levels. The
              default color comes from the lines, if shown. The
              default family and size come from `layout.font`.
          labelformat
              Sets the contour label formatting rule using d3
              formatting mini-language which is very similar to
              Python, see: https://github.com/d3/d3-3.x-api-
              reference/blob/master/Formatting.md#d3_format
          operation
              Sets the constraint operation. "=" keeps regions equal
              to `value` "<" and "<=" keep regions less than `value`
              ">" and ">=" keep regions greater than `value` "[]",
              "()", "[)", and "(]" keep regions inside `value[0]` to
              `value[1]` "][", ")(", "](", ")[" keep regions outside
              `value[0]` to value[1]` Open vs. closed intervals make
              no difference to constraint display, but all versions
              are allowed for consistency with filter transforms.
          showlabels
              Determines whether to label the contour lines with
              their values.
          showlines
              Determines whether or not the contour lines are drawn.
              Has an effect only if `contours.coloring` is set to
              "fill".
          size
              Sets the step between each contour level. Must be
              positive.
          start
              Sets the starting contour level value. Must be less
              than `contours.end`
          type
              If `levels`, the data is represented as a contour plot
              with multiple levels displayed. If `constraint`, the
              data is represented as constraints with the invalid
              region shaded as specified by the `operation` and
              `value` parameters.
          value
              Sets the value or values of the constraint boundary.
              When `operation` is set to one of the comparison values
              (=,<,>=,>,<=) "value" is expected to be a number. When
              `operation` is set to one of the interval values
              ([],(),[),(],][,)(,](,)[) "value" is expected to be an
              array of two numbers where the first is the lower bound
              and the second is the upper bound.
          """
  
imports: from plotly.basedatatypes import BaseTraceHierarchyType
  import copy
label_desc: Use image node_id 23 for calling the Contours obj's underlying member method code with example usage: obj._prop_descriptions() and returns: str