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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 form_number(self):
 		""" 		Returns the model's form number, a helpful heuristic for classifying tides. 		"""

		k1, o1, m2, s2 = (
			np.extract(self.model['constituent'] == c, self.model['amplitude'])
			for c in [constituent._K1, constituent._O1, constituent._M2, constituent._S2]
		)
		return (k1+o1)/(m2+s2)