text: from pyspark.sql.types import StringType, DateType
  from bs4 import BeautifulSoup as BS
  fieldnames = [f["name"] for f in field_metadata]
  transforms = {item['name']:item['transform'] for item in field_metadata if "transform" in item}
  field_metadata = [
      {"name": "created_at","type": DateType()},
      {"name": "text", "type": StringType()},
      {"name": "source", "type": StringType(), 
           "transform": lambda s: BS(s, "html.parser").text.strip()
      }
  ]
  