### Task:

You have to write a function `pattern` which returns the following Pattern(See Examples) upto (2n-1) rows, where n is parameter.

* Note:`Returning` the pattern is not the same as `Printing` the pattern.

#### Parameters:
    
    pattern(        n        );
                    ^                     
                    |                     
             Term upto which   
           Basic Pattern(this)     
                should be         
                 created            
                                  
                                
#### Rules/Note:
* If `n < 1` then it should return "" i.e. empty string.
* `The length of each line is same`, and is equal to the length of longest line in the pattern i.e (2n-1).
* Range of Parameters (for the sake of CW Compiler) :
  + `n ∈ (-∞,100]`

### Examples:

* pattern(5):

        1       1
         2     2 
          3   3  
           4 4   
            5    
           4 4   
          3   3  
         2     2 
        1       1
       
        
* pattern(10):

        1                 1
         2               2 
          3             3  
           4           4   
            5         5    
             6       6     
              7     7      
               8   8       
                9 9        
                 0         
                9 9        
               8   8       
              7     7      
             6       6     
            5         5    
           4           4   
          3             3  
         2               2 
        1                 1
    
* pattern(15):

        1                           1
         2                         2 
          3                       3  
           4                     4   
            5                   5    
             6                 6     
              7               7      
               8             8       
                9           9        
                 0         0         
                  1       1          
                   2     2           
                    3   3            
                     4 4             
                      5              
                     4 4             
                    3   3            
                   2     2           
                  1       1          
                 0         0         
                9           9        
               8             8       
              7               7      
             6                 6     
            5                   5    
           4                     4   
          3                       3  
         2                         2 
        1                           1
    
[List of all my katas]("http://www.codewars.com/users/curious_db97/authored")

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "from itertools import chain\n\ndef pattern(n):\n    def f():\n        length = 2*n - 1\n        lines = [' '] * length\n        for i in chain(range(1, n+1), range(n-1, 0, -1)):\n            x = str(i % 10)\n            lines[i-1] = lines[-i] = x\n            yield lines\n            lines[i-1] = lines[-i] = ' '\n    return '\\n'.join(map(''.join, f()))"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'pattern'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 6846