fix(README): update it

README.md

-# pySoleilControl
-Useful python tools for SOLEIL control system.
-
-The ultimate aim is to provide tools that can be used in a shell prompt, ipython prompt or in python applications (such as GUI).
-
-Under construction, the first brick is a module to retrieve data from the Tango Archiver.
-
-## ArchiveExtractor
+# ArchiveExtractor
 This module brings some functions to extract data from HDB/TDB.
 
+## Quick example
 Usage example, with an ipython prompt
 
 ```python
-In [1]: import pySoleilControl.ArchiveExtractor as AE
+In [1]: import ArchiveExtractor as AE
 
 In [2]: # Looking for an attribute in HDB
    ...: AE.findattr("ans/dg/*dcct*")
@@ -24,7 +18,7 @@ Out[2]:
  'ANS/DG/DCCT-CTRL/lifeTimeErr']
 
 In [3]: # Get data between two dates, this return a pandas.Dataframe object
-   ...: AE.ExtrBetweenDates('ANS/DG/DCCT-CTRL/current', '2021-12-13', '2021-12-13-12:00')
+   ...: AE.extract('ANS/DG/DCCT-CTRL/current', '2021-12-13', '2021-12-13-12:00')
 INFO:Perform ExtractBetweenDates (ans/dg/dcct-ctrl/current, 2021-12-13 00:00:00, 2021-12-13 12:00:00)
 Out[3]: 
 2021-12-13 00:00:00    450.993568
@@ -40,75 +34,48 @@ Out[3]:
 2021-12-13 12:00:00     15.005410
 Length: 42725, dtype: float64
 
-In [4]: # Get min, max and mean with a 10 minute window
-   ...: d=AE.ExtrBetweenDates_MinMaxMean('ANS/DG/DCCT-CTRL/current', '2021-12-13', '2021-12-13-12:00', timeInterval='10m')
-
-In [5]: d
-Out[5]: 
-                            Min        Mean         Max
-2021-12-13 00:05:00  449.762286  450.619654  451.617095
-2021-12-13 00:15:00  449.761171  450.676306  451.595391
-2021-12-13 00:25:00  449.764910  450.684333  451.606520
-2021-12-13 00:35:00  449.766284  450.688881  451.655843
-2021-12-13 00:45:00  449.766808  450.716444  451.678886
-...                         ...         ...         ...
-2021-12-13 11:15:00   15.435944   15.495834   15.552427
-2021-12-13 11:25:00   15.325022   15.383286   15.437459
-2021-12-13 11:35:00   15.214556   15.270340   15.326395
-2021-12-13 11:45:00   15.106309   15.163566   15.219333
-2021-12-13 11:55:00   15.003812   15.056515   15.110022
-
-[72 rows x 3 columns]
-
-
-In [6]: # Activate inline matplotlib
-   ...: %matplotlib
-Using matplotlib backend: TkAgg
-
-In [6]: # Simply plot
-   ...: d.plot()
-
-In [7]: # ipython prompt supports autocompletion. The doc of function can be quickly read by adding a '?'
-    ...: AE.ExtrBetweenDates?
-Signature: AE.ExtrBetweenDates(attribute, dateStart, dateStop=None, db='H')
+```
+## Main function help
+
+
+```
+Signature: AE.extract(attr, date1, date2=None, method='nearest', db='H')
 Docstring:
-Query attribute data from an archiver database, get all points between dates.
-Use ExtractBetweenDates.
+Access function to perform extraction between date1 and date2.
+Can extract one or several attributes.
+date1 and date2 can be both exact date, or one of two can be a time interval that will be taken relative to the other.
 
-Parameters
-----------
-attribute : String
-    Name of the attribute. Full Tango name i.e. "test/dg/panda/current".
 
-dateStart : datetime.datetime, string
-    Start date for extraction. If string, it will be parsed.
-    Example of string format %Y-%m-%d-%H:%M:%S or less precise.
+Parameters:
+-----------
+attr: string, list, dict
+    Attribute(s) to extract.
+    If string, extract the given attribute, returning a pandas.Series.
+    If list, extract attributes and return a list of pandas.Series.
+    If a dict, extract attributes and return a dict of pandas.Series with same keys.
 
-dateStop : datetime.datetime, string, None
-    Stop date for extraction.
+date1, date2: string, datetime.datetime, datetime.timedelta, None
+    Exact date, or duration relative to date2.
     If string, it will be parsed.
-    Example of string format %Y-%m-%d-%H:%M:%S or less precise.
-    If None, it takes the current date and time.
-    Default is None (now).
+    A start date can be given with string format '%Y-%m-%d-%H:%M:%S' or less precise (ie '2021-02', '2022-11-03' '2022-05-10-21:00'.i..).
+    A duration can be given with string format 'Xu' where X is a number and u is a unit in ('m':minutes, 'h':hours, 'd':days, 'M':months)
+    A datetime.datetime object or datetime.timedelta object will be used as is.
+    date2 can be None. In that case it is replaced by the current time.
+
+method: str
+    Method of extraction
+        'nearest': Retrieve nearest value of date1, date2 is ignored.
+        'between': Retrive data between date1 and date2.
 
 db: str
     Which database to look in, 'H' or 'T'.
 
-Exceptions
-----------
-ValueError
-    The attribute is not found in the database.
+```
 
-Returns
--------
-[date, value] : array
-    date : numpy.ndarray of datetime.datime objects
-        Dates of the values
-    value : numpy.ndarray
-        Archived values
-File:      ~/GrpDiagnostics/RBT/pySoleilControl/ArchiveExtractor.py
-Type:      function
+## For developpers
 
+### Contribute
 
+There is a simple test directory with only a manual test scipt.
+Please run and check it before proposing merge.
 
-```