class_docstr: Grandparent class for plotting
  modes. Serves as interface for
  registration, lookup, and init
  of modes.
  
  To create a new plot mode,
  inherit from PlotModeBase
  or one of its children, such
  as PlotSurface or PlotCurve.
class_docstr_tok: ["Grandparent","class","for","plotting","modes",".","Serves","as","interface","for","registration",",","lookup",",","and","init","of","modes",".","To","create","a","new","plot","mode",",","inherit","from","PlotModeBase","or","one","of","its","children",",","such","as","PlotSurface","or","PlotCurve","."]
code: def _fill_intervals(self, intervals):
      # copy default intervals
      self.intervals = [PlotInterval(i) for i in self.intervals]
      # track i_vars used so far
      v_used = []
      # fill copy of default
      # intervals with given info
      for i in range(len(intervals)):
          self.intervals[i].fill_from(intervals[i])
          if self.intervals[i].v is not None:
              v_used.append(self.intervals[i].v)
      # Find any orphan intervals and
      # assign them i_vars
      for i in range(len(self.intervals)):
          if self.intervals[i].v is None:
              u = [v for v in self.i_vars if v not in v_used]
              if len(u) == 0:
                  raise ValueError("length should not be equal to 0")
              self.intervals[i].v = u[0]
              v_used.append(u[0])
  
imports: from .plot_interval import PlotInterval
  from .plot_object import PlotObject
  from .util import parse_option_string
  from sympy.core.symbol import Symbol
  from sympy.core.sympify import sympify
  from sympy.geometry.entity import GeometryEntity
  from sympy.utilities.iterables import is_sequence
label_desc: Use image node_id 10 for calling the PlotMode obj's underlying member method code with example usage: obj._fill_intervals(intervals) without return types