def __init__(self, event_type, event_properties=None):
self.event_type = event_type<EOL>if event_properties:<EOL><INDENT>if isinstance(event_properties, types.StringTypes):<EOL><INDENT>event_properties = [event_properties]<EOL><DEDENT><DEDENT>else:<EOL><INDENT>event_properties = []<EOL><DEDENT>self.event_properties = event_properties<EOL>self.filters = []<EOL>
Create an Event expression.

        :param event_type: The type of the event to query for.
        :type event_type: str
        :param event_properties: Any properties to fetch from the event.
        :type event_properties: `str` or `list(str)`

        >>> request_time = EventExpression('request', 'elapsed_ms')
        >>> print(request_time.event_type)
        request
        >>> print(request_time.event_properties)
        ['elapsed_ms']
        >>> print(request_time.eq('path', '/').gt('elapsed_ms', 100).lt(
        ...     'elapsed_ms', 1000))  # doctest:+NORMALIZE_WHITESPACE
        request(elapsed_ms).eq(path, "/").gt(elapsed_ms, 100).lt(elapsed_ms,
                1000)