remote: error: refusing to update checked out branch: refs/heads/master
remote: error: By default, updating the current branch in a non-bare repository
remote: error: is denied, because it will make the index and work tree inconsistent
remote: error: with what you pushed, and will require 'git reset --hard' to match
remote: error: the work tree to HEAD.
remote: error:
remote: error: You can set 'receive.denyCurrentBranch' configuration variable to
remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into

alias apt=apt-get
alias dnf=apt-get

1234567890
2468024680
3692581470
4826048260
5050505050
6284062840
7418529630
8642086420
9876543210
0000000000

        /* reject string values for 'start' parameter */
        if (PyUnicode_Check(result)) {
            PyErr_SetString(PyExc_TypeError,
                "sum() can't sum strings [use ''.join(seq) instead]");
            Py_DECREF(iter);
            return NULL;
        }
        if (PyBytes_Check(result)) {
            PyErr_SetString(PyExc_TypeError,
                "sum() can't sum bytes [use b''.join(seq) instead]");
            Py_DECREF(iter);
            return NULL;
        }
        if (PyByteArray_Check(result)) {

r=range(1,11)
for j in r:print''.join(`i*j%10`for i in r)

Can save 1 byte by switching to Python 3 if spaces are allowed between digits:
r=range(1,11)
for j in r:print(*(str(i*j%10)for i in r))

abort 'GCC does not exist on your system or it is not in your PATH.
Please install GCC or add it to your PATH to continue.' unless `which gcc` && $?.success?