[ISSUE 142] new python rule : AvoidMultipleIfElseStatement

ecocode-rules-specifications/src/main/rules/EC2/php/EC2.asciidoc

@@ -31,6 +31,7 @@ if ($nb == 0) {
 } else {
     $nb = -1;
 }
+return $nb;
 ```
 
 ## Compliant Code Example

ecocode-rules-specifications/src/main/rules/EC2/python/EC2.asciidoc

@@ -0,0 +1,54 @@
+If we are using too many conditional IF, ELSEIF or ELSE statements it will impact performance.
+We can think of using a switch statement instead of multiple if-else if possible, or refactor code
+to reduce number of IF, ELSEIF and ELSE statements. Sometimes called "complexity cyclomatic".
+MATCH-CASE statement has a performance advantage over if – else.
+
+## Functional rules
+- one variable must be used maximum twice in IF / ELSEIF / ELSE statements at the same level - WARNINGs :
+- IF and ELSEIF statements use explicitly variable names !
+- ELSE statements use implicity variable names !
+- one variable must be used maximum twice in IF / ELSEIF / ELSE statements at differents hierarchical levels
+- we can assume that if one variable is used three times or more, we should :
+- use a MATCHS-CASE statement instead
+- or refactor the code if possible
+
+## Non-compliant Code Example
+
+NON compliant, because `nb` is used 4 times :
+- 2 explicit times in IF statements
+- 2 implicit times in ELSE statements
+
+```python
+index = 1
+nb = 2
+...
+if nb == 0:
+    nb = index
+elif nb == 1:
+    nb = index * 2
+elif nb == 2:
+    nb = index * 3
+else:
+    nb = -1
+return nb
+```
+
+## Compliant Code Example
+
+MATCH-CASE statement solution + refactor solution
+
+```python
+index = 1
+nb = 2
+...
+match nb:
+    case 0:
+        nb = index * (nb + 1)
+    case 1:
+        nb = index * (nb + 1)
+    case 2:
+        nb = index * (nb + 1)
+    case _:
+        nb = -1
+return nb
+```