sagemathgh-38153: Remove imports pyx
    
removing a few unused imports in some pyx files

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
    
URL: sagemath#38153
Reported by: Frédéric Chapoton
Reviewer(s): Matthias Köppe

Author: Release Manager

src/sage/graphs/graph_decompositions/tree_decomposition.pyx

@@ -105,7 +105,6 @@ Methods
 
 from sage.sets.set import Set
 from sage.misc.cachefunc import cached_function
-from sage.features import PythonModule
 from sage.sets.disjoint_set import DisjointSet
 from sage.rings.infinity import Infinity
 from sage.graphs.distances_all_pairs cimport c_distances_all_pairs

src/sage/libs/gmp/pylong.pyx

@@ -22,11 +22,9 @@ AUTHORS:
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 2 of the License, or
 # (at your option) any later version.
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 #*****************************************************************************
 
-
-from cpython.object cimport Py_SIZE
 from cpython.long cimport PyLong_FromLong
 from cpython.longintrepr cimport _PyLong_New, py_long, digit, PyLong_SHIFT
 from sage.cpython.pycore_long cimport (ob_digit, _PyLong_IsNegative,

src/sage/libs/ntl/ntl_ZZ_pX.pyx

@@ -29,7 +29,6 @@ include 'decl.pxi'
 from cpython.object cimport Py_EQ, Py_NE
 from sage.cpython.string cimport char_to_str
 from sage.rings.integer cimport Integer
-from sage.libs.ntl.convert cimport PyLong_to_ZZ
 from sage.libs.ntl.ntl_ZZ cimport ntl_ZZ
 from sage.libs.ntl.ntl_ZZ_p cimport ntl_ZZ_p
 from sage.libs.ntl.ntl_ZZ_pContext cimport ntl_ZZ_pContext_class

src/sage/libs/pari/convert_sage_real_mpfr.pyx

@@ -2,11 +2,11 @@
 
 from cypari2.stack cimport new_gen
 from cypari2.paridecl cimport *
-from cysignals.signals cimport sig_on, sig_off
+from cysignals.signals cimport sig_on
 
 from sage.libs.gmp.mpz cimport *
 from sage.libs.mpfr cimport *
-from sage.libs.mpfr.types cimport mpfr_t, mpfr_prec_t
+from sage.libs.mpfr.types cimport mpfr_prec_t
 from sage.rings.real_mpfr cimport RealField_class, RealField
 
 

src/sage/matrix/matrix2.pyx

@@ -82,7 +82,6 @@ from cysignals.signals cimport sig_check
 
 from sage.categories.fields import Fields
 from sage.categories.integral_domains import IntegralDomains
-from sage.categories.principal_ideal_domains import PrincipalIdealDomains
 from sage.categories.rings import Rings
 from sage.misc.lazy_string import lazy_string
 from sage.misc.randstate cimport current_randstate

src/sage/matrix/matrix_laurent_mpolynomial_dense.pyx

@@ -15,22 +15,22 @@ AUTHOR:
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 from sage.matrix.constructor import identity_matrix
-from sage.rings.polynomial.laurent_polynomial_ring_base import LaurentPolynomialRing_generic
+
 
 cdef class Matrix_laurent_mpolynomial_dense(Matrix_generic_dense):
     """
     Dense matrix over a Laurent multivariate polynomial ring over a field.
     """
     def laurent_matrix_reduction(self):
         """
-        From a matrix `self` of Laurent polynomials, apply elementary operations
-        to obtain a matrix `P` of polynomials such that the variables do not divide
-        no column and no row.
+        From a matrix ``self`` of Laurent polynomials, apply elementary operations
+        to obtain a matrix ``P`` of polynomials such that the variables do not divide
+        any column and any row.
 
         OUTPUT:
 
-        Three matrices `L`, `P`, `R` such that ``self` equals `L P R`, where `L` and
-        `R` are diagonal with monomial entries.
+        Three matrices ``L``, ``P``, ``R`` such that ``self`` equals ``L P R``,
+        where ``L`` and ``R`` are diagonal with monomial entries.
 
         EXAMPLES:
 
@@ -56,20 +56,22 @@ cdef class Matrix_laurent_mpolynomial_dense(Matrix_generic_dense):
         res = self.__copy__()
         for j, rw in enumerate(res.rows()):
             for t in R.gens():
-                n = min(mon.degree(t) for a in rw for cf, mon in a)
+                n = min(mon.degree(t) for a in rw for _, mon in a)
                 res.rescale_row(j, t ** -n)
                 mat_l.rescale_col(j, t ** n)
         for j, cl in enumerate(res.columns()):
             for t in R.gens():
-                n = min(mon.degree(t) for a in cl for cf, mon in a)
+                n = min(mon.degree(t) for a in cl for _, mon in a)
                 res.rescale_col(j, t ** -n)
                 mat_r.rescale_row(j, t ** n)
         res = res.change_ring(R.polynomial_ring())
         return mat_l, res, mat_r
 
     def _fitting_ideal(self, i):
         r"""
-        Return the `i`-th Fitting ideal of the matrix. This is the ideal generated
+        Return the `i`-th Fitting ideal of the matrix.
+
+        This is the ideal generated
         by the `n - i` minors, where `n` is the number of columns.
 
         INPUT:

src/sage/matrix/matrix_mpolynomial_dense.pyx

@@ -24,9 +24,7 @@ from sage.matrix.matrix2 cimport Matrix
 from sage.rings.polynomial.multi_polynomial_libsingular cimport MPolynomialRing_libsingular
 from sage.rings.polynomial.polynomial_singular_interface import can_convert_to_singular
 
-from sage.libs.singular.function import singular_function, lib
-
-from cysignals.signals cimport sig_on, sig_off
+from sage.libs.singular.function import singular_function
 
 
 cdef class Matrix_mpolynomial_dense(Matrix_generic_dense):
@@ -518,7 +516,7 @@ cdef class Matrix_mpolynomial_dense(Matrix_generic_dense):
 
     def determinant(self, algorithm=None):
         """
-        Return the determinant of this matrix
+        Return the determinant of this matrix.
 
         INPUT:
 

src/sage/matroids/graphic_matroid.pyx

@@ -87,7 +87,7 @@ AUTHORS:
 # ****************************************************************************
 
 from sage.matroids.matroid cimport Matroid
-from copy import copy, deepcopy
+from copy import copy
 from sage.matroids.utilities import newlabel, split_vertex, sanitize_contractions_deletions
 from itertools import combinations
 from sage.rings.integer import Integer

src/sage/matroids/linear_matroid.pyx

@@ -111,7 +111,7 @@ Methods
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
 
-from copy import copy, deepcopy
+from copy import copy
 from itertools import product
 
 from cpython.object cimport Py_EQ, Py_NE

src/sage/modular/arithgroup/farey_symbol.pyx

@@ -40,7 +40,7 @@ from .congroup_gamma import Gamma_class
 from .congroup_sl2z import SL2Z
 from sage.modular.cusps import Cusp
 
-from sage.misc.decorators import options, rename_keyword
+from sage.misc.decorators import options
 from sage.misc.cachefunc import cached_method
 from sage.structure.richcmp cimport richcmp_not_equal
 

src/sage/plot/plot3d/base.pyx

@@ -52,7 +52,6 @@ AUTHORS:
 from cpython.list cimport *
 
 import os
-import sys
 import zipfile
 
 from functools import reduce

src/sage/quadratic_forms/ternary.pyx

@@ -13,7 +13,7 @@ Helper code for ternary quadratic forms
 # ****************************************************************************
 
 from sage.arith.misc import gcd, inverse_mod, xgcd
-from sage.matrix.constructor import matrix, identity_matrix, diagonal_matrix
+from sage.matrix.constructor import matrix
 from sage.misc.prandom import randint
 from sage.rings.finite_rings.integer_mod import mod
 from sage.rings.integer_ring import ZZ

src/sage/rings/complex_interval.pyx

@@ -61,7 +61,7 @@ from sage.libs.gmp.mpz cimport mpz_sgn, mpz_cmpabs_ui
 from sage.libs.mpfr cimport *
 from sage.libs.mpfi cimport *
 from sage.libs.flint.fmpz cimport *
-from sage.libs.mpfr cimport MPFR_RNDU, MPFR_RNDD
+from sage.libs.mpfr cimport MPFR_RNDU
 from sage.arith.constants cimport LOG_TEN_TWO_PLUS_EPSILON
 
 from sage.structure.element cimport FieldElement

src/sage/rings/polynomial/polynomial_rational_flint.pyx

@@ -12,17 +12,16 @@ AUTHOR:
 - Sebastian Pancratz
 """
 
-#*****************************************************************************
+# ****************************************************************************
 #          Copyright (C) 2010 Sebastian Pancratz <[email protected]>
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 2 of the License, or
 # (at your option) any later version.
-#                  http://www.gnu.org/licenses/
-#*****************************************************************************
+#                  https://www.gnu.org/licenses/
+# ****************************************************************************
 
-from cysignals.memory cimport check_allocarray, sig_free
 from cysignals.signals cimport sig_on, sig_str, sig_off
 
 from cpython.long cimport PyLong_AsLong

src/sage/sets/family.pyx

@@ -49,7 +49,6 @@ from sage.categories.finite_enumerated_sets import FiniteEnumeratedSets
 from sage.categories.infinite_enumerated_sets import InfiniteEnumeratedSets
 from sage.misc.cachefunc import cached_method
 from sage.misc.call import AttrCallObject
-from sage.misc.lazy_import import LazyImport
 from sage.rings.infinity import Infinity
 from sage.rings.integer import Integer
 from sage.sets.finite_enumerated_set import FiniteEnumeratedSet