Apply #1391 with additional doctest

pwnlib/tubes/process.py

@@ -857,6 +857,7 @@ def libs(self):
                 return pwnlib.elf.elf.ELF(self.executable).maps
 
         # Enumerate all of the libraries actually loaded right now.
+        maps = {}
         for line in maps_raw.splitlines():
             if '/' not in line: continue
             path = line[line.index('/'):]
@@ -881,6 +882,13 @@ def libc(self):
         Returns an ELF for the libc for the current process.
         If possible, it is adjusted to the correct address
         automatically.
+
+        Example:
+
+        >>> p = process("/bin/cat")
+        >>> p.libc # doctest: +ELLIPSIS
+        ELF('/lib64/libc-...so')
+        >>> p.close()
         """
         from pwnlib.elf import ELF