def filter_by_conditional_statement(self, statement):
_filt_values, _filt_datetimes = self._filter_by_statement(statement)<EOL>if self._enumeration is None:<EOL><INDENT>self._get_mutable_enumeration()<EOL><DEDENT>col_obj = self._enumeration['<STR_LIT>'][self._collection_type]<EOL>collection = col_obj(self.header.duplicate(), _filt_values, _filt_datetimes)<EOL>collection._validated_a_period = self._validated_a_period<EOL>return collection<EOL>
Filter the Data Collection based on a conditional statement.

        Args:
            statement: A conditional statement as a string (e.g. a > 25 and a%5 == 0).
                The variable should always be named as 'a' (without quotations).

        Return:
            A new Data Collection containing only the filtered data