Returns True if some multigraph can realize the sequence.
A list of integers
True if deg_sequence is a multigraphic degree sequence and False if not.
The worst-case run time is \(O(n)\) where \(n\) is the length of the sequence.
S. L. Hakimi. “On the realizability of a set of integers as degrees of the vertices of a linear graph”, J. SIAM, 10, pp. 496-506 (1962).