MAINT: minor refactoring in docscrape (#297)

* MAINT: rm unnecessary elses in _str methods

* rm unused indent method from NDS

* rm unused header method from NDS

numpydoc/docscrape.py

@@ -431,28 +431,22 @@ def _str_header(self, name, symbol='-'):
         return [name, len(name)*symbol]
 
     def _str_indent(self, doc, indent=4):
-        out = []
-        for line in doc:
-            out += [' '*indent + line]
-        return out
+        return [' '*indent + line for line in doc]
 
     def _str_signature(self):
         if self['Signature']:
             return [self['Signature'].replace('*', r'\*')] + ['']
-        else:
-            return ['']
+        return ['']
 
     def _str_summary(self):
         if self['Summary']:
             return self['Summary'] + ['']
-        else:
-            return []
+        return []
 
     def _str_extended_summary(self):
         if self['Extended Summary']:
             return self['Extended Summary'] + ['']
-        else:
-            return []
+        return []
 
     def _str_param_list(self, name):
         out = []
@@ -525,8 +519,7 @@ def _str_index(self):
             out += ['   :%s: %s' % (section, ', '.join(references))]
         if output_index:
             return out
-        else:
-            return ''
+        return ''
 
     def __str__(self, func_role=''):
         out = []
@@ -546,23 +539,11 @@ def __str__(self, func_role=''):
         return '\n'.join(out)
 
 
-def indent(str, indent=4):
-    indent_str = ' '*indent
-    if str is None:
-        return indent_str
-    lines = str.split('\n')
-    return '\n'.join(indent_str + l for l in lines)
-
-
 def dedent_lines(lines):
     """Deindent a list of lines maximally"""
     return textwrap.dedent("\n".join(lines)).split("\n")
 
 
-def header(text, style='-'):
-    return text + '\n' + style*len(text) + '\n'
-
-
 class FunctionDoc(NumpyDocString):
     def __init__(self, func, role='func', doc=None, config={}):
         self._f = func