code: def monthly_data():
      df = pd.DataFrame(
          {
              "ts": pd.date_range("2020-01-01", periods=100, freq="MS"),
              "y": range(100),
          }
      )
      return df
  
imports: import pandas
  import pytest
  from testfixtures import LogCapture
  from greykite.common.logging import LOGGER_NAME
  from greykite.framework.templates.auto_model_template import get_auto_silverkite_model_template
  from greykite.framework.templates.autogen.forecast_config import EvaluationPeriodParam
  from greykite.framework.templates.autogen.forecast_config import ForecastConfig
  from greykite.framework.templates.model_templates import ModelTemplateEnum
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_DAILY_90
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_HOURLY_1
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_HOURLY_24
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_HOURLY_168
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_HOURLY_336
  from greykite.framework.templates.simple_silverkite_template_config import SILVERKITE_WEEKLY
label_desc: Use image node_id 4 for calling a global function with example usage: monthly_data() and returns: df