docs: def fromdeltas(cls, deltas):
  		"""
  		Construct an offsetvector from a dictionary of offset
  		deltas as returned by the .deltas attribute.
  
  		Example:
  
  		>>> x = offsetvector({"H1": 0, "L1": 10, "V1": 20})
  		>>> y = offsetvector.fromdeltas(x.deltas)
  		>>> y
  		offsetvector({'V1': 20, 'H1': 0, 'L1': 10})
  		>>> y == x
  		True
  
  		See also .deltas, .fromkeys()
  		"""
  		return cls((key, value) for (refkey, key), value in deltas.items())