Fixes cycle basis for multiedges

[abhayptp]

It fixes #27538. Now, cycle_basis() for multiedges works correctly.

sage: G = Graph([(1,2),(2,3),(2,3),(3,4),(1,4),(1,4),(4,5),(5,6),(4,6),(6,7)],multiedges=True)
sage: G.cycle_basis()
[[1, 4], [2, 3], [4, 3, 2, 1], [6, 5, 4]]

Currently, I am importing Graph from sage.graphs.graph in cycle_basis function to create instance of Graph. Suggestions are invited for any alternate approach.

CC: @dcoudert @rajat1433

Component: graph theory

Branch/Commit: u/gh-abhayptp/fixes_cycle_basis_for_multiedges @ b2c82ec

Reviewer: David Coudert

Issue created by migration from https://trac.sagemath.org/ticket/27563

[abhayptp]

Branch: u/gh-abhayptp/fixes_cycle_basis_for_multiedges

[abhayptp]

Commit: b2c82ec

[abhayptp]

New commits:

b2c82ec

Fixes cycle basis for multiedges

[abhayptp]

comment:4

Duplicate. See #27538.

[dcoudert]

Reviewer: David Coudert

[dcoudert]

comment:8

We can close this ticket.