code: def clear_principal_credit_string(self):
          
          # Implemented from template for osid.repository.AssetForm.clear_title_template
          if (self.get_principal_credit_string_metadata().is_read_only() or
                  self.get_principal_credit_string_metadata().is_required()):
              raise errors.NoAccess()
          self._my_map['principalCreditString'] = dict(self._principal_credit_string_default)
docs: Removes the principal credit string.
  
          raise:  NoAccess - ``Metadata.isRequired()`` is ``true`` or
                  ``Metadata.isReadOnly()`` is ``true``
          *compliance: mandatory -- This method must be implemented.*