code: def flatten_dict(self, data: dict, prefix: str = ""):
      flat_data = {}
      for key, value in data.items():
          if isinstance(value, dict):
              flattened_sub_dict = self.flatten_dict(value, f"{key}_")
              flat_data.update(flattened_sub_dict)
          elif isinstance(value, list):
              for i, item in enumerate(value):
                  if isinstance(item, dict):
                      flattened_sub_dict = self.flatten_dict(
                          item, f"{key}_{i}_"
                      )
                      flat_data.update(flattened_sub_dict)
                  else:
                      flat_data[f"{prefix}{key}_{i}"] = item
          else:
              flat_data[f"{prefix}{key}"] = value
      return flat_data
  
imports: import pandas
  from mindsdb.integrations.libs.api_handler import APITable
  from mindsdb_sql.parser import ast
  from mindsdb.integrations.utilities.sql_utils import extract_comparison_conditions
label_desc: Use image node_id 1 for calling the PurchasesTable obj's underlying member method code with example usage: obj.flatten_dict(data, prefix) and returns: flat_data