Graphical degree sequence

Test sequences for graphiness.

is_graphical(sequence[, method]) Returns True if sequence is a valid degree sequence.
is_digraphical(in_sequence, out_sequence) Returns True if some directed graph can realize the in- and out-degree sequences.
is_multigraphical(sequence) Returns True if some multigraph can realize the sequence.
is_pseudographical(sequence) Returns True if some pseudograph can realize the sequence.
is_valid_degree_sequence_havel_hakimi(…) Returns True if deg_sequence can be realized by a simple graph.
is_valid_degree_sequence_erdos_gallai(…) Returns True if deg_sequence can be realized by a simple graph.