class_docstr: Select candidate for body pose estimation.
  
  Args:
      mapIdx(list): Part Affinity Fields map index, default is None.
      limbSeq(list): Peak candidate map index, default is None.
code: def __init__(self, mapIdx: list = None, limbSeq: list = None):
      if mapIdx and limbSeq:
          self.mapIdx = mapIdx
          self.limbSeq = limbSeq
      else:
          self.mapIdx = [
              [31, 32],
              [39, 40],
              [33, 34],
              [35, 36],
              [41, 42],
              [43, 44],
              [19, 20],
              [21, 22],
              [23, 24],
              [25, 26],
              [27, 28],
              [29, 30],
              [47, 48],
              [49, 50],
              [53, 54],
              [51, 52],
              [55, 56],
              [37, 38],
              [45, 46],
          ]
          self.limbSeq = [
              [2, 3],
              [2, 6],
              [3, 4],
              [4, 5],
              [6, 7],
              [7, 8],
              [2, 9],
              [9, 10],
              [10, 11],
              [2, 12],
              [12, 13],
              [13, 14],
              [2, 1],
              [1, 15],
              [15, 17],
              [1, 16],
              [16, 18],
              [3, 17],
              [6, 18],
          ]
  
imports: import base64
  import math
  from typing import Callable
  import cv2
  import numpy
  from scipy.ndimage import gaussian_filter
label_desc: Use image node_id 1 to create a new Candidate object  with example: obj = Candidate(mapIdx, limbSeq)