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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fromdeltas(cls, deltas):
 		""" 		Construct an offsetvector from a dictionary of offset 		deltas as returned by the .deltas attribute. 		Example: 		offsetvector({'V1': 20, 'H1': 0, 'L1': 10}) 		True 		See also .deltas, .fromkeys() 		"""

		return cls((key, value) for (refkey, key), value in deltas.items())