code: def dasherize(value):
      
      value = value.strip()
      value = re.sub(r'([A-Z])', r'-\1', value)
      value = re.sub(r'[-_\s]+', r'-', value)
      value = re.sub(r'^-', r'', value)
      value = value.lower()
      return value
docs: Dasherizes the passed value.