docstr: Returns a dict mapping hover dimension names to flattened arrays.
  
  Note that `Quad` glyphs are used when given 1-D coords but `Patches` are
  used for "irregular" 2-D coords, and Bokeh inserts data into these glyphs
  in the opposite order such that the relationship b/w the `invert_axes`
  parameter and the need to transpose the arrays before flattening is
  reversed.
code: def _collect_hover_data(self, element, mask=(), irregular=False):
      """
      Returns a dict mapping hover dimension names to flattened arrays.
  
      Note that `Quad` glyphs are used when given 1-D coords but `Patches` are
      used for "irregular" 2-D coords, and Bokeh inserts data into these glyphs
      in the opposite order such that the relationship b/w the `invert_axes`
      parameter and the need to transpose the arrays before flattening is
      reversed.
      """
      transpose = (
          self.invert_axes if irregular else not self.invert_axes
      )
  
      hover_dims = element.dimensions()[3:]
      hover_vals = [
          element.dimension_values(hover_dim, flat=False)
          for hover_dim in hover_dims
      ]
      hover_data = {}
      for hdim, hvals in zip(hover_dims, hover_vals):
          hdat = hvals.T.flatten() if transpose else hvals.flatten()
          hover_data[dimension_sanitizer(hdim.name)] = hdat[mask]
      return hover_data
  
imports: import sys
  import numpy
  import param
  from bokeh.models import CustomJSHover, DatetimeAxis
  from ...core.util import cartesian_product, dimension_sanitizer, isfinite
  from ...element import Raster
  from ..util import categorical_legend
  from .chart import PointPlot
  from .element import ColorbarPlot, LegendPlot
  from .selection import BokehOverlaySelectionDisplay
  from .styles import base_properties, fill_properties, line_properties, mpl_to_bokeh
  from .util import bokeh33, bokeh34, colormesh
label_desc: Use image node_id 2 for calling the QuadMeshPlot obj's underlying member method code with example usage: obj._collect_hover_data(element, mask, irregular) and returns: hover_data