def __add__(self, other):
return self.copy().__iadd__(other)<EOL>
Extend method. Used for '+'

.. rubric:: Example

>>> family_a = Family(template=Template(name='a'))
>>> family_b = Family(template=Template(name='a'))
>>> family_c = family_a + family_b
>>> print(family_c)
Family of 0 detections from template a


Can only extend family with the family of detections from the same
template:

>>> family_a = Family(template=Template(name='a'))
>>> family_b = Family(template=Template(name='b'))
>>> family_c = family_a + family_b # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
NotImplementedError: Templates do not match


Can extend by adding a detection from the same template.

>>> family_a = Family(template=Template(name='a'))
>>> detection = Detection(
...     template_name='a', detect_time=UTCDateTime(), no_chans=5,
...     detect_val=2.5, threshold=1.23, typeofdet='corr',
...     threshold_type='MAD', threshold_input=8.0)
>>> family = family_a + detection
>>> print(family)
Family of 1 detections from template a


Will not work if detections are made using a different Template.

>>> family_a = Family(template=Template(name='a'))
>>> detection = Detection(
...     template_name='b', detect_time=UTCDateTime(), no_chans=5,
...     detect_val=2.5, threshold=1.23, typeofdet='corr',
...     threshold_type='MAD', threshold_input=8.0)
>>> family = family_a + detection # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
NotImplementedError: Templates do not match


Cannot extent a family with a list, or another object.

>>> family_a = Family(template=Template(name='a'))
>>> family = family_a + ['albert'] # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
NotImplementedError: Can only extend with a Detection of Family object.