docstr: Tests if dimension is scalar in each subpath.
code: def isscalar(cls, dataset, dim, per_geom=False):
      """
      Tests if dimension is scalar in each subpath.
      """
      dim = dataset.get_dimension(dim)
      if dim in cls.geom_dims(dataset):
          return False
      elif per_geom:
          return all(
              isscalar(v) or len(list(unique_array(v))) == 1
              for v in dataset.data[dim.name]
          )
      dim = dataset.get_dimension(dim)
      return len(dataset.data[dim.name].unique()) == 1
  
imports: import sys
  from collections import defaultdict
  import numpy
  import pandas
  from ..dimension import dimension_name
  from ..util import isscalar, unique_array, unique_iterator
  from .interface import DataError, Interface
  from .multipath import MultiInterface, ensure_ring
  from .pandas import PandasInterface
label_desc: Use image node_id 17 for calling the SpatialPandasInterface obj's underlying member method code with example usage: obj.isscalar(cls, dataset, dim, per_geom) and returns: unknown, False, all