class_docstr: This dataset describes a monthly count of the number of observed sunspots for
  just over 230 years (1749-1983).
  
  The units are a count and there are 2,820 observations. The source of the dataset is
  credited to Andrews & Herzberg (1985).
  
  References:
      .. [#1] Andrews, D. F. and Herzberg, A. M., "Data: A Collection of Problems from
          Many Fields for the Student and Research Worker,"
          New York: Springer-Verlag, 1985.
      .. [#2] https://stat.ethz.ch/R-manual/R-devel/library/datasets/html/sunspots.html
      .. [#3] https://r-data.pmagunia.com/dataset/r-dataset-package-datasets-sunspots
      .. [#4] Avishek Pal, PKS Prakash, "Practical Time Series Analysis"
          https://github.com/PacktPublishing/Practical-Time-Series-Analysis/
code: def __init__(
      self,
      url: str = None,
  ):
      self.data_folder = os.path.realpath(
          os.path.join(
              os.path.dirname(os.path.realpath(__file__)),
              "../data",
              "sunspots_data",
          )
      )
      self.data_file = os.path.realpath(
          os.path.join(self.data_folder, "sunspots.csv")
      )
      sunspots_url = (
          url
          if url is not None
          else "https://raw.githubusercontent.com/PacktPublishing/Practical-Time-Series-Analysis/master/Data%20Files/monthly-sunspot-number-zurich-17.csv"
      )
  
      if not os.path.exists(self.data_file):
          response = requests.get(sunspots_url)
          data = pd.read_csv(
              StringIO(response.text),
              skiprows=0,
              nrows=2820,
          )
          data.columns = ["time", "sunspots"]
          data["time"] = pd.to_datetime(data["time"], format="%Y-%m")
  
          data.to_csv(self.data_file, index=False)
  
file_path: AIX360/aix360/datasets/sunspots_dataset.py
imports: import os
  import math
  from io import StringIO
  import requests
  import pandas
label_desc: Use image node_id 1 to create a new SunspotDataset object  with example: obj = SunspotDataset(url)